you read the title, i need homebrew artifacts for an artifact focused campaign. any ideas that go with them are also welcome

Depends what you are after .


The ring of Gyges is a favorite of mine  -  It's a ring of invisibility from Plato that inspired lord of the rings. It has the power to protect one from the consequences of their actions allowing them to get away with great evil if they desire. Plato used it to argue that morality is independent of consequences.  In Dnd a ring that made you invisible even to gods and divine judgment after death could  be very valuable to evil doers resulting in a plot similar to suicide squad, hell to pay ( which has a get out of hell free card) where a number of morally questionable factions compete over the item to protect themselves from hell.   In terms of effect it would be a  ring of invisibility  with protection from divination spells similar to mind blank.

 The target is also unaffected by anything that would sense its emotions or alignment, read its thoughts, or magically detect its location, and no spell—not even Wish—can gather information about the target, observe it remotely, or control its mind.

 I also like the "Holy" grail- The exact abilities vary depending on the story.  Generally speaking it's an object that represents divinity that may be sought to discover divine truths or achieve a miracle. It could be blood of a dead god like the actual holy grail but I prefer the idea of a grand machine built by ancient spell casters, it doesn't really matter. The point is that it's an object that can be sought by both the selfish and the selfless. A scholar may seek it  to discover hidden truths, an evil person may seek it for power.  I also like to make it kind of evil, either because it has become corrupted or powered through questionable means. 

Maybe you could do something similar to the deathly hallows, were there are 3 artifacts that, when used together, have immense power, but are still powerful when used seperatly

figured I should post the actual campaign idea...

here goes.

an extreamly powerful wizard has used an incredibly powerful artifact called The Monkey's Paw to create duplicates of legendary and artifact magic items, however, due to the nature of The Monkey's Paw, all of the items are defective. the wizard, finding this out, decided to auction off the cursed items of power. a buyer of an item has hired the party to track down the cursed items and destroy them. to rephrase my original question, I need defective or cursed versions of artifacts and legendary magic items(yes that includes the already cursed and might as well be cursed ones like The Crook Of Rao, and The Deck Of Many Things). the campaign will (hopefully) end with the retrieval of The Monkey's Paw, the evil artifact that started it all. weather they destroy it is up to them. its power is truly great...

Oh if you want broken ones then 

the ring of winter except the following effect  is always  on around you as an aura  and when you spend all charges you freeze into a statue.  In other words you leave a trail of winter and eventually freeze.  You can also use the objects sentience to have it encourage people to use the ring for evil and expend the charges.

You can expend 1 charge as an action and use the ring to lower the temperature in a 120-foot-radius sphere centered on a point you can see within 300 feet of you. The temperature in that area drops 20 degrees per minute, to a minimum of –30 degrees Fahrenheit. Frost and ice begin to form on surfaces once the temperature drops below 32 degrees. This effect is permanent unless you use the ring to end it as an action, at which point the temperature in the area returns to normal at a rate of 10 degrees per minute.

A double edge luck blade. You get 3 wish's which take the form of good luck (that means no obvious magic instead things occur by happenstance). However, when you spend all the wish's or lose the blade everything backfires until you die. 

The Deck of... Wait What! Just a random, comedic, "what the hell?!" version of the Deck of Many Things

The Bag of Huh, a bag of holding you can live in.

The Eye and Hand of Vecna, same as the original but slowly turns you into a corpse

Armour of In-Vulnerabililty : While wearing this armour you have resistance to non-magical damage and vulnerability to magical damage.

Axe of the Dwarvish Lords : While attuned to this item you are drunk and poisoned (even if you would normally be immune to poison), you have a +3 to attack and damage rolls with this item and a +2 to Constitution. Everytime you attack with this weapon you magically summon one of : magma mephit, dust mephit, mud mephit, or magmin within 5ft of you that is hostile towards you.

Cloak of Invisibility/Ring : When you turn invisible 3 invisible stalkers are summoned and attack you.

Holy Avenger : replace it's normal aura with: Divine Light while this weapon is drawn from its sheath it creates blinding white light in a 10 ft radius (all creatures within this aura or that look at creatures within the area are blinded for 1 minute), bright light in a radius of 60 ft, and dim light for the next 60 ft radius.

Orb of Dragonkind: Curse: while attuned to this item you can only speak in Draconic, and if you finish a long rest while attune to this item you are transformed into a random dragon wyrmling until you finish a long rest without being attuned to it.

Robe of the Archmagi: Curse: whenever you cast a spell while attune to the item it targets yourself or it's area of effect is centered on yourself.

Rod of Resurrection: Curse: when you cast a spell from this rod you are immediately reduced to 0 hit points.

Wave: Curse: while attuned to this item you can only breath in water.

Vorpal Sword: Curse: when you roll a 1 on an attack with this weapon you accidentally lop off one of your own limbs with it.

To make it fun make the item have a 50-50 of working properly if a player tries to use it make them do a high low - on a fail they do another high low - it either fails of targets friendlies. 

Quote from IMPLAYS >>

 

The Eye and Hand of Vecna, same as the original but slowly turns you into a corpse

 Do the eye and hand not already do that?

Quote from Solarsyphon >>

Quote from IMPLAYS >>

 

The Eye and Hand of Vecna, same as the original but slowly turns you into a corpse

 Do the eye and hand not already do that?

 To my knowledge, they don't but they might. I just remember it bonding to you and they kinda become less corpse-y.

Quote from IMPLAYS >>

Quote from Solarsyphon >>

Quote from IMPLAYS >>

 

The Eye and Hand of Vecna, same as the original but slowly turns you into a corpse

 Do the eye and hand not already do that?

 To my knowledge, they don't but they might. I just remember it bonding to you and they kinda become less corpse-y.

that is correct. you might get possessed by vecna, but you don't get turned into a corpse.

I changed it so that you believe you are vecna. you aren't.

armor of inn-vulnerability: when wearing this armor it grants resistance to bludgeoning,slashing, and piercing damage from nonmagical sources, but when the wearer is inside an inn they gain vulnerability to all damage until they exit the inn.