I have a wood elf arcane trickster in the campaign i'm playing, and came up with a simple combination where you take the find familiar spell at lvl 3 and the elven accuracy feat at lvl 4. Then while in combat you command your familiar (no action required) to distract the enemy by using the help action. This will give you permanent triple advantage unless your familiar dies. Just wondering if anyone else would use this combo?

There is no such thing as triple advantage. Advantage doesn’t stack. No matter how many sources provide you with advantage, you only roll two dice. 
What’s more. No matter how many sources you have, they can all be canceled by a single disadvantage. 15 kinds of advantage and one disadvantage equals a straight roll.

After a conversation with my GM about how to use a familiar and being respectful of game balance, they let my swashbuckler/chainlock use the familiar this way. The familiar is invisible and so they ruled that unless the opponent has blindsight, truesight, or some other preternatural ability to detect the familiar it will not be targeted. It is still open to area of effect spells unless it moves far enough away each round. Basically, the familiar readies an action to use the help action when they see the character is about to act. It allows the familiar to sweep down and buffet, prod, or just add a sound to distract while its master takes advantage, then flies back out of danger without the AoO due to invisiblity.

You can make an opportunity attack when a hostile creature THAT YOU CAN SEE moves out of your reach. PHB p195.

A normal familiar needs flyby, which severely limits your options to the owl. If you are unconcerned with any of this, then any familiar can provide the help action at its own endangerment if your DM acts against it.

Quote from Xalthu >>

There is no such thing as triple advantage. Advantage doesn’t stack. No matter how many sources provide you with advantage, you only roll two dice. 
What’s more. No matter how many sources you have, they can all be canceled by a single disadvantage. 15 kinds of advantage and one disadvantage equals a straight roll.

 While it is not officially called triple advantage elven accurract allows you to re-roll one of the dice whenever you roll with advantage, as you will always pick the lower or the two dice to reroll this is the same as rolling 3 dice and using the highest and this is often unofficially called triple advantage.

"Triple advantage" is not however guaranteed as Xalthu pointed out if there is a source of disadvantage (for example the target has Blur cast on them) you will have a straight roll for your attack (as the help action cancels the disadvantage)

After a conversation with my GM about how to use a familiar and being respectful of game balance, they let my swashbuckler/chainlock use the familiar this way. The familiar is invisible and so they ruled that unless the opponent has blindsight, truesight, or some other preternatural ability to detect the familiar it will not be targeted. It is still open to area of effect spells unless it moves far enough away each round. Basically, the familiar readies an action to use the help action when they see the character is about to act. It allows the familiar to sweep down and buffet, prod, or just add a sound to distract while its master takes advantage, then flies back out of danger without the AoO due to invisiblity.

You can make an opportunity attack when a hostile creature THAT YOU CAN SEE moves out of your reach. PHB p195.

A normal familiar needs flyby, which severely limits your options to the owl. If you are unconcerned with any of this, then any familiar can provide the help action at its own endangerment if your DM acts against it.

Readying an action does not allow you to also move. You can only ready a move (which is the same as readying the dash action) OR ready an action so you can only use a readied help action if you are alrready within 5ft of the enemy.

Having said that you may not need ot ready the help action, if the familiar uses the help action on its turn to "feint, distract the target, or in some other way team up to make its ally’s attack more effective."  Its ally's first attack roll is made with advantage as long as it takes polace before the familiars next turn.  There is nothing to prevent the familiar from flying away after it has done the help action.

While the enemy can not make an opportunity attack against the familiar (unless it can see it) it can target it with an attack on its turn (at disadvantage) if it konws where it is. It could also use an AOE attack so it does not suffer from not being able to see it.

After a conversation with my GM about how to use a familiar and being respectful of game balance, they let my swashbuckler/chainlock use the familiar this way. The familiar is invisible and so they ruled that unless the opponent has blindsight, truesight, or some other preternatural ability to detect the familiar it will not be targeted. 

This is ridiculous not even pc's are hidden without steath aka hide action. Hearing can still locate invisible creatures to allow Targeting.  But an " dm will not attack pact" should only be for "narrative non-combatants" like actual pets. Part of the reason find familiar is only first level is the hp weakness. 

Yeah, it totally works. Your familiar is a perfectly reasonable target for monsters, but if it's invisible, they'll have a bit harder of a time trying to kill it. And, I mean, any attacks directed at the familiar are attacks that aren't directed at you. So it's still kinda good even if it does get attacked and killed.

Quote from Xalthu >>

There is no such thing as triple advantage. Advantage doesn’t stack. No matter how many sources provide you with advantage, you only roll two dice. 
What’s more. No matter how many sources you have, they can all be canceled by a single disadvantage. 15 kinds of advantage and one disadvantage equals a straight roll.

I know. sorry, I wasn't very specific. but the reason I said "triple advantage" is that elven accuracy lets you reroll one dice if you have advantage (the familiar gives the advantage) and are using your intelligence, wisdom, or dexterity modifiers for the attack. this basically gives you "triple advantage"

Yes, it's a good combo.  Use Find Familiar to summon an Owl, and on the owl's turn, have it fly to the enemy, help you to give you Advantage, and fly away without take an opportunity attack due to flyby!

Faerie Fire if necessary, and Magic Missile or Eldritch Blast.  That way you can target the familiar as well as other members of the party.

This is actually a pretty well known and, RAW, a completely legal tactic in D&D. That said, some DM's are stricter about what they'll let players do with Familiars... they still have animal-level intelligence, and may not know how to properly pull off this tactic. Another argument I've seen is the idea that you can only command your Familiar to Help, but not also command them to then move to a specific location away from the opponent. Personally I think those restrictions are unnecessary and mostly used by DM's who just shouldn't allow Find Familiar in their game in the first place if they have so much trouble dealing with players taking advantage of the spell, but I remember a fairly long thread arguing about this sort of thing with DM's on both sides of the issue arguing at length about why FF should or shouldn't be able to be used in this manner.

Just keep in mind that, no matter what side of the issue your DM falls on, your Familiar still only has 1 or 2 HP, and if they get shot with an arrow or something it's gonna take you an hour and 10gp to get them back, so don't be surprised if your Familiar gets ganked early in a dungeon delve and you have to rely on other spells and abilities for the rest of the day. Luckily as a Rogue you can still Hide as a bonus action to get yourself advantage as needed.

Using your familiar to get you Advantage in combat is completely legit, it's just that the familiar is somewhat fragile. As an Arcane Trickster, though, you have lots of options to get Advantage. People have already mentioned a few, but I would like to point out Steady Aim, which is an optional rule from Tasha's Cauldron of Everything, as long as you don't move for the entire turn you can take a Bonus Action to give one of your attacks Advantage.

Quote from Ophidimancer >>

Using your familiar to get you Advantage in combat is completely legit, it's just that the familiar is somewhat fragile. As an Arcane Trickster, though, you have lots of options to get Advantage. People have already mentioned a few, but I would like to point out Steady Aim, which is an optional rule from Tasha's Cauldron of Everything, as long as you don't move for the entire turn you can take a Bonus Action to give one of your attacks Advantage.

 I did find a way to make the familiar less fragile, there is a feat called inspiring leader from Tashas or xanathars I can't remember what book, but it gives temporary hit points equal to your level + charisma modifier to up to 6 creatures for a day. this would make the familiar have enough hp to not get 1 shot every time 

Quote from ShhinySilver >>

 

Quote from Xalthu >>

There is no such thing as triple advantage. Advantage doesn’t stack. No matter how many sources provide you with advantage, you only roll two dice. 
What’s more. No matter how many sources you have, they can all be canceled by a single disadvantage. 15 kinds of advantage and one disadvantage equals a straight roll.

I know. sorry, I wasn't very specific. but the reason I said "triple advantage" is that elven accuracy lets you reroll one dice if you have advantage (the familiar gives the advantage) and are using your intelligence, wisdom, or dexterity modifiers for the attack. this basically gives you "triple advantage"

 I would probably call this double advantage instead of triple. You have advantage, rolling two dice. Adding one more die roll goes from single to triple advantage? Lol, I know it doesn’t really matter, we can both call it whatever we want. It still works the same and is a good combo. And if your Arcanre Trickster makes it to 13th level they can just use their mage hand to get the advantage. 

I hope this has helped you all to break the game a little more.

Quote from theHumanChris >>

After a conversation with my GM about how to use a familiar and being respectful of game balance, they let my swashbuckler/chainlock use the familiar this way. The familiar is invisible and so they ruled that unless the opponent has blindsight, truesight, or some other preternatural ability to detect the familiar it will not be targeted. It is still open to area of effect spells unless it moves far enough away each round. Basically, the familiar readies an action to use the help action when they see the character is about to act. It allows the familiar to sweep down and buffet, prod, or just add a sound to distract while its master takes advantage, then flies back out of danger without the AoO due to invisiblity.

You can make an opportunity attack when a hostile creature THAT YOU CAN SEE moves out of your reach. PHB p195.

A normal familiar needs flyby, which severely limits your options to the owl. If you are unconcerned with any of this, then any familiar can provide the help action at its own endangerment if your DM acts against it.

My one issue with this is how much an invisible familiar can actually Help against a target that can't see it. It's one thing for an Owl to fly in front of something's face and distract it, but if the familiar is invisible then it would have to do something other than just be there in order to be effective. If I were the DM in that case I'd probably have the familiar make an attack roll, and if it "hits", the Help action is successful. 

To be fair, I have a bit of a bias against the Help action because I've seen it abused a lot. 

One thing to remember is that in order for you to gain an invisible familiar, a character has to invest in a subclass as a Warlock. It feels powerful as a feature, but most think that chain is lacking, Investment of the Chain Master helped a bit, but most feel Tome or Blade is superior.

The Help action does not have to be a direct targeted interaction, but a minimally invasive interaction. Imagine how vexing it is when something like a cobweb is on your face, or a drop of ice cold rain water drips down the back of your neck unexpectedly. Also, Invisibility on the familiar protects it from get opportunity attacked when moving with some exceptions, but not from area affect spells.

If you were to rule that the familiar has to make a successful attack, then that would hold true for every time a character attempts to help another. If this were a policy, then the help action would become useless because you could just have everyone try it and hope one person makes it instead of hedging your bets against supporting the most skilled character. Maybe have the support character make a DC equal to half the target DC? Currently, using Help eats the character's action, and this would make it have some chance of failure increasing the situations intensity if it is in a time sensitive scenario without making it a useless tactic.

Quote from jd2319>>

My one issue with this is how much an invisible familiar can actually Help against a target that can't see it. It's one thing for an Owl to fly in front of something's face and distract it, but if the familiar is invisible then it would have to do something other than just be there in order to be effective.

Yes, it can make a noise or brush up against the target is a distracting manner.

Yes, that combo is quite common. However, it is not as OP as it seems. It's pretty easy to get the familiar killed, and you'll have to re-summon it after the battle (at a cost, of course).

Also keep in mind that the help action gives advantage to the next attack that is made. So if you have more than one attack for whatever reason, only the first one has advantage. Or if the target receives any other attack before you attack.

Quote from Feykiller >>

Yes, that combo is quite common. However, it is not as OP as it seems. It's pretty easy to get the familiar killed, and you'll have to re-summon it after the battle (at a cost, of course).

Also keep in mind that the help action gives advantage to the next attack that is made. So if you have more than one attack for whatever reason, only the first one has advantage. Or if the target receives any other attack before you attack.

 Actually the Help Action in combat gives advantage to a specific ally, not to the next attack against the target.

Alternatively, you can aid a friendly creature in attacking a creature within 5 feet of you. You feint, distract the target, or in some other way team up to make your ally’s attack more effective. If your ally attacks the target before your next turn, the first attack roll is made with advantage.

Quote from Xalthu >>

There is no such thing as triple advantage. Advantage doesn’t stack. No matter how many sources provide you with advantage, you only roll two dice. 
What’s more. No matter how many sources you have, they can all be canceled by a single disadvantage. 15 kinds of advantage and one disadvantage equals a straight roll.

 Technically this would be double advantage.

"Whenever you have advantage on an attack roll using Dexterity, Intelligence, Wisdom, or Charisma, you can reroll one of the dice once."

This is mechanically and statistically indistinguishable from just rolling 3 dice.