Quote from Cynroc >>

GOO -- The Cacophony of Voices (Homebrew). It's a hollowed out Illithid compound where the psionic energy of thousands of jarred humanoid brains formed a sentient thought entity that grows in power the more brains are added to Its cacophony.

Great idea. I love it.

Similarly, I made a Fiend Patron using a Vestige based on the 3.5e Binder class: 

The Vile Whispers, a Vestige of the Hag Countess

Legend: The Hag Countess, also known as Malagard, and her three sisters once inhabited the dark forests of the Feywild but were exiled to the Lower Planes by Titania, and the Seelie of the Summer Court.  Upon her eventual demise at the hands of Asmodeus, her sisters fled the Nine Hells to a hidden cavern on the material plane.  Fearing the archdevil’s wrath, the sisters purged themselves of all memory of the Countess.  Thus, the Vile Whispers of the Hag Countess, formed from the cast-off memories of her dark sisters, were left to eternally wander the caverns of Toril. 

Appearance: The Vile Whispers have no true form, however, for brief moments, the Hag Countess may appear in the form of a crooked old crone made entirely of ash with great curving horns and black feathery wings. 

Pact-Making: The Vile Whispers haunt the darkest caves and deepest hollows of Toril causing madness in those who linger too long in their frightful presence.   Certain individuals with a predisposition for madness or an inherently wicked nature may understand the logic of the vile rantings, slowly unlocking the secrets of Hag Countess’ profane power.  Warlocks of the Vile Whispers thus risk their sanity in return for the eldritch secrets of the dead countess.  

Motivation: The Vile Whispers are but echoes of the once powerful night hag and have no singular motivation for sharing their secrets with Witches and Warlocks.  At times, the Whispers foretell the return of Malagard and her ascension to Goodhood, other times, they seem content to simply sow the seeds of madness in hapless travelers who wander their dark caverns.  Regardless, pupils of the Whispers are urged to seek revenge against Titania and Asmodeus, and other Archfey or Archdevils that serve them, whenever the opportunity arises. 

I am working on a 5th Ed. interpretation, of an old character.

Here his mother was Half elf/half arch-fey, his father was Grey(high) Elf.  Oak Harts mother and father were killed by a dragon, to save the child the father gave the dragon lethal indigestion.

Oak-hart presents as wild elf, so couldn't live with the fathers folk.

Was not presenting as arch Fey, so couldn't survive Grandmothers court.

Childhood was spent playing with mortals, as a charlatan. 

His Fey ancestry began asserting itself and he is taking the warlock class.

His Arch-fey Patron is his own beloved Grandma

I made a Paladin (Green Knight) Oath of the Ancients and I also put levels into Warlock Fey patron. 

My characters back story is that he and his brother (twin) are both Aasimars. And they were born to a country farmer and his wife. Their names are a play on the British comedy "The Black Adder". So my brothers name is Edmond Blackadder and my characters name is Robert Blackadder. The village they were born near is a old and very superstitious place. The locals started to notice the boys doing things like healing a injured woman or how the boys eyes were golden. The locals thought it was witch craft or the work of evil as pretty much all magic is seen in that area. So one day while the boys family was out in the fields tending crops or the animals a local man decided he would take the boys away and rid the village of this evil magic before something terrible happened to them all. So he sneaked onto the farm and told the boys that a young boy had fallen ill in the forest and the two young boys gifts were his only chance. The boys wishing to help of course agreed and went with him. The man took the boys into the dark woods, a place avoided by the locals due to tales of beasts and creatures known to eat men with little effort or care. Once the man had figured he had taken the boys deep enough into the woods he told them to wait in a glade and he would check to find exactly where the little boy was. The man took off as fast as possible and was soon gone. Unfortunately for the man, predators took notice of his quick flight and his life ended in the woods. The animals did eventually find the boys but the boys celestial presence kept the animals more curious than anything. Soon a presence in the forest noticed the intrusion upon its domain and came to see what had the animals and the forest in general disturbed. Before night had fallen a large woman elven  in appearance with deep green hair and vines growing around her body appeared. She was beautiful and the forest seemed to almost bow before her. She took notice of the boys heritage of celestial nature and decided after a few moments to take these two under her care. She would see them raised as future guardians of the natural order and she began instructing them in the ways of the forest and animals. She taught them many things including how to use magic (her magic). The boys began to call her "Mother Leaf" and she let this happen as it seemed to help her cause with making the boys see her as a parental figure. Soon the boys got older as boys do. And she decided that they had learned enough from her to satisfy her interests. She sent for one of her devoted among the Elves and soon a warrior answered her summons. She instructed him to take these two and begin their training of swords and armor. She promised him a reward if his efforts proved successful. He agreed and took the two human cubs under his guidance and began their training as warriors. Again time passed and the boys reached the age of 19, long passed into adulthood by now both boys had decided to become Paladins and take up the Oath of the Ancients and pledge their faith in nature and to Mother Leaf as well. 

I haven't yet played this character but this is the back story I came up with. To me it covers the Warlock patron and the source of faith the two use for their Paladin abilities. Mother Leaf is a one stop shop for my character and his brother. If anyone likes this back story or wish to take it and rework it feel free. I know its a little bare bones but I prefer this as it leaves more chances of things I didn't see to come about through a DM's imagination.

Forgive me because I am brand new to all of this, but can you possibly bring in pacts like from Greek mythology? I had this idea of Charon the ferryman, and having to bring in souls for him. Since some people I believe kinda see him as a grim reaper maybe the weapon a scythe? Again forgive me of my noobness ^^"" i've been trying to do my own research and i'm at the point of being burnt out with so much info. I'm also assuming this would also have to fly with my DM, any thoughts, suggestions, or complaints?

Absolutely, Charon would make a good Patron for Undying, GOO or even Hexblade. He’s from the lower planes so you could probably even go with the Fiend Patron. Great idea. The source material for patrons is really endless. What direction are you leaning?

Well I was thinking of a hex ranger. I use the monster slayers "hunter sense" actually as a curse for the blood line. Yes it helps them in battle figuring out the monsters weakness, but the down side is whenever the carrier sleeps they relive death of each carrier waking up with possible bruises, cuts, etc that heal overtime. Through the  life of the blood line they have tried to find a cure for this curse but have failed. Now when Alestors father passed he left him a note on what could be the cure and that is to make a pact with Kharon. In order to fill Kharons needs Alestor would have to send two souls a week to Kharon, of course also doing the coins on the eyes so the soul may pass on. Im still trying to figure out what else to do and add to that. 

Also fun fact with the curse: Even though Alestor is a half elf, he needs a full rest to fully recover unlike most elfs and half elfs due to the curse that haunts him in his sleep.

I just noticed I used a K this entire time for Charon lmao

So this is a Hexblade Warlock/Monster Hunter Ranger multiclassed character? You planning on more levels in Ranger or Warlock?

Pretty much, and that I am not too sure yet. I plan on playing around with it more tomorrow night. Maybe get the warlock to 5 and then rest in ranger, we are only at level 3 right now so i'm just going to play around with some ideas. Any suggestions? And what do you think of the backstory so far, a bit much?

Just remember that warlock spell slot lvl boosts and invocations boost happen at odd lvls. So make sure you're getting what you want out of them.

The two humanoids a week bit could get dicey depending on the campaign setting. Out in the wild, just you and your party could mean killing them to keep the quota. And then what happens when you're stranded in the middle of nowhere? It could work for an urban setting, just remember that you're using a serial killer theme for yourself. So the "getting away with it" will be the harder part.

And now that I think about it a little more... Suggestion of a change of patron. (Again I don't know your setting but) you may want to swap out Kharon. As a ranger it just seems like an odd choice. And take a look at Malar (lesser-deity of the hunt).

(https://forgottenrealms.fandom.com/wiki/Malar) -- Malarites believed that it was an honor to Malar to make one's killing bloody and long. His followers sometimes formed in bands, called "Hunts". While forbidden to slay the young or the pregnant, Hunts typically followed his dogma and evoked wanton slaughter in Malar's name. Malarites were generally frowned upon by civilization, as they tended to wreak havoc in their wake. One exception where the worship of Malar was allowed was in Cormyr.

One of the most respected servants of Malar was Garmos Saernclaws, who was responsible for the gospel of Saernclaws by which all priests of Malar were bound, ensuring that hunts remained clean and poison-free.

He gives you a wider range to fill your quota (the beating hearts of being of a certain CR for instance). But if you know what your want, don't let me tell you otherwise.

I second Malar. The bloodthirsty god of the wild hunt fits perfect!

I don't know how interesting or original it is, but here it goes:

My Undying Warlock is the last heiress of a noble house. After having her family wiped out by a rival family, she makes a pact with her grand-grand-grand and so forth grandmother, who's a lich. My character's family actually came into nobility after beating the evil lich queen, while unbeknown to the rest of the world she was actually part of their family. Because of that they secretly kept a little of her phylactery and sealed it, along with the rest of her remains, away deep inside their families manor, never to be seen again. With the rest of her family murdered however, and no one else left she can turn to, my character foolishly approaches her grandmother and makes her an offer. Her grandmother will share some of her power with my character, under the condition that she can't use the powers given to her to kill others. She will also be constantly haunted by her grandmother's whispers and should she ever give in to temptation, her grandmother won't only be freed, but she will also use her body as her new vessel.
Can our hero suppress her desire for revenge and withstand the temptation of her grandmother's whispers? Find out next time.

I also used the old god Ithaqua from Lovecraft for my great old one warlock and a tsukumogami for my hexblade warlock, but those are even less original than the one above, so you probably don't want to hear too much about them.

With the release of the Acquisitions Incorporated sourcebook, I'm going to be trying out a Verdan Warlock with the "patron" instead being the literal manifestation of their ongoing mutations, with a touch of That-Which-Endures for flavor.

Hexblade, with the weapons conjured literally coming from the black blood the race possesses. The various invocations being chosen come as mutations as well. For instance, Devil's Sight is going to be an actual change to the character's eyes; either becoming pitch black, taking on some unnatural glow in the darkness, or even becoming more animalistic.

Honestly if you want Warlock ideas for patrons then Japanese anime is often a good source for ideas.  While the premise of many of the show's protagonists getting their powers has nothing technically to do with Warlocks. If you just ignore X character got Y powers or Abilities from Z being,  then you can find allot of interesting ideas to take and then twist to your own preferences. Games are also good places as well to borrow from. 

 But for me I like to use ideas that a DM won't struggle with. Sometimes you might have this really great idea for a Warlock backstory but if it's too far out there, then the DM might either veto it, or just decide to not use it for the story telling of their campaign. Also having a outlandish patron can backfire for you the players. You might have a DM who will rise to the challenge of working with your crazy patron idea and before you know it that patron isn't a funny Haha idea but a dragging chain around your characters neck. I enjoy creative back stories and Warlocks or Sorcerers really do feed that. But I also try to think about what I would do if someone made this character and had this patron idea. If I was the DM how could I use that in the campaign and what would the patron be like for the player once the bargaining is over and the player is stuck with the pact. And also never think that you would be the only one that patron has at their beck and call should you try double crossing them or refusing to honor the agreement for the power you hold. A evil patron can always target your friends and family or those who give you favorable treatment.  When word gets around that people who are friendly with you end up skinned and turned inside out. You can imagine how hard life for your character can become or it's effect on the campaign. 

I don't usually play warlocks because I tend to prefer to play "light" characters rather than "dark" ones. Of course there's non-dark fey warlocks and GOOs don't have to be creepy and there's the celestial patrons but most of the rest of the options imply the dark. So, I've been trying to think of ways to reflavor patrons to be light.

Like a hexblade warlock receiving their weapon in a Lady-of-the-Lake or Sword-in-the-Stone situation. Or Link pulling the Master Sword from the pedestal (Eldritch Blast == sword beams?). Or an undying warlock having the non-evil version of the undead as a patron.

I did also have a new idea for a type of patron and I've been scouring the internet to see if anyone else had the same idea. It would have to be a homebrew build I think. Basically, rather than the current patrons, the patron would be a living king/queen, emperor/empress, pharaoh, dynasty, etc who has the divine right of rulership. Fanatical warlocks might be able to draw power from that right of rulership to serve queen and country, serving as soldiers and agents when needed. 

Quote from TheAntesse >>

I don't usually play warlocks because I tend to prefer to play "light" characters rather than "dark" ones. Of course there's non-dark fey warlocks and GOOs don't have to be creepy and there's the celestial patrons but most of the rest of the options imply the dark. So, I've been trying to think of ways to reflavor patrons to be light.

 
It would help if there were more Invocations that weren't all dark-and-gritty; by my count, close to half of them are named or themed in a manner that seems "dark", with the rest being merely "neutral."

I know, I know, you can always reskin them, but that you would have to do that kind of pigeon-holes the class right off the bat.

Quote from RodTheBard >>

Quote from TheAntesse >>

I don't usually play warlocks because I tend to prefer to play "light" characters rather than "dark" ones. Of course there's non-dark fey warlocks and GOOs don't have to be creepy and there's the celestial patrons but most of the rest of the options imply the dark. So, I've been trying to think of ways to reflavor patrons to be light.

 
It would help if there were more Invocations that weren't all dark-and-gritty; by my count, close to half of them are named or themed in a manner that seems "dark", with the rest being merely "neutral."

I know, I know, you can always reskin them, but that you would have to do that kind of pigeon-holes the class right off the bat.

 Kthanid is sort of a loophole for Great Old One patrons...it is essentially a "good" Cthullu, one that inspires unusual feelings of joy, rather than maddening terror...it'd be an interesting to be a disciple of this patron. You'd likely be support, as a kthanid is strongly anti-violence...instead, they actually keep hostile Great Old One's at bay by modifying their memories and instilling feelings of dread whenever they attempt to attack others.

A Celestial patron provides a more direct way to handle a "light" character...their skills are based around healing, surviving, and opposing darkness. Your patron literally embodies justice and benevolence.

Plus, you get to be a creepy cleric.

one of my old pcs was a warlock with homebrewded wizard spells 

(was aculy a wizard but went mad and started talking to a bed post)

the bed post is his patron