Hi all! Other than Paladin's Oath of the Watcher, are there any subclasses, or even magic items, that focus on combating aberrations either primarily or in tandem with other focuses? Im in the end game of our years long campaign, lvl19 which is set in the far realm, we've defeated Cosmic Horrors, our Queen is stuck in the palace with an army of occupying mind flayers and we're about to come face to face with Kyuss. I also have a huge feeling my current PC may meet his end this next session...

Ranger and Favored Enemy Aberrations.

Horizon Walker Ranger is specifically about combating threats from other planes of existence. 

Aberrant Mind Sorcerer has aberration connections and could pretty easily form the basis of someone trying to hunt down aberrations. Perhaps the character was hunting them, and their first contact twisted them into something magical. Or perhaps they were born with exposure to aberrations, and trying to gain understanding or revenge gave their life purpose.  Lots you could do there.

Great Old One pact would have you working for some aberration, which could mean trying to stop others.

In a similar vein to Oath of Watchers, one might think that the Arcana Domain Cleric (with its Arcane Abjuration Channel Divinity and Dr. Strange flavor) might be a good choice as well, but, surprisingly, aberrations are not one of the creature types they can target. 

Both Horizon Walker Ranger and Arcana Domain Cleric feel like they should also specialize against aberrations, but they don't (outside of Favored Enemy for any ranger). Even many of the anti-otherwordly creature spells don't include aberrations.

Alternatively, Great Old One/Fathomless Warlock or Aberrant Mind Sorcerer aren't necessarily specialized against aberrations, but fit the flavor.

Outside of specific class/subclass features, you can shore up defenses against aberrations by looking for things like psychic damage resistance, good WIS>INT>CON saves, and the ability to reliably escape a grapple preferably without your using your action. Offensively, aberrations often don't have great STR or DEX and you can usually guess which one they're better at based on size.

Druids as a class are set up pretty well to oppose aberrations. When you stand for the natural order, something so unnatural is inherently offensive.

In general there aren't really subclasses or classes that focus too heavily on one sort of encounter because it makes the game boring when those encounters aren't present. For example, lots of folks want a designated anti-spellcaster subclass, but spellcasters are a small share of monsters.

I should have mentioned that my current PC's sister is influenced by the occupying illithids and she is essentially an Aberrant Mind sorcerer, so I wanted to steer clear of that choice (as obvious as it is) but I'll do it if I have to!!! haha We have a paladin in our party who I get the sense may not like someone stepping on his class' toes, hence this enquiry.

So my options thus far:

• Paladin Oath of the Watchers
• Druid Circle of Dreams
• Ranger Horizon Walker (but a little underwhelming)
• Aberrant Mind Sorcerer

Our party currently consists of Fighter Brute (the archived UA), Arcane Trickster, Evo Wizard, Swords Bard, Open Fist Monk, Crown Paladin and me, Alchemist, the party healer. There's a general thing in our party of trying not to crossover classes (one of the reasons  why I went Artificer all those years ago)

Quote from Heartofjuyomk2 >>

In general there aren't really subclasses or classes that focus too heavily on one sort of encounter because it makes the game boring when those encounters aren't present. For example, lots of folks want a designated anti-spellcaster subclass, but spellcasters are a small share of monsters.

 It's also why there aren't any subclasses themed around fighting dragons or undead, either, despite those being two classic kit/prestige class options from older editions.

My Arcana Cleric / Transmutation Wizard kinda does the opposite, collecting pieces from kills and finding something interesting to graph them onto. This party is more on the evil side. 

Quote from Spikepit >>

So my options thus far:

• Paladin Oath of the Watchers
• Druid Circle of Dreams
• Ranger Horizon Walker (but a little underwhelming)
• Aberrant Mind Sorcerer

Our party currently consists of Fighter Brute (the archived UA), Arcane Trickster, Evo Wizard, Swords Bard, Open Fist Monk, Crown Paladin and me, Alchemist, the party healer. There's a general thing in our party of trying not to crossover classes (one of the reasons  why I went Artificer all those years ago)

Most non-cleric casters make good anti- aberration PCs, really. 

Stars Druid - woooooo theme

Fey Wanderer Ranger - Feywild is somewhat the opposite of Outer Dimension Monsters. (P.S. HWalker Rangers mostly catch up to other Rangers at high level play.)

Also, just by making your PC a githyanki or githzerai you are already anti-illithid by theme.

I'll add to this conversation that illithids (and many other aberrations) tend to exhibit two main modes of attack: grappling and psychic damage. There's no real subclass that challenges both of these modes directly. What you could do is develop countermeasures in game. In previous editions, there were magic items designed specifically to fight illithids including armor that automatically slices a creature attempting to grapple you, a magic ring that creates a field of electricity damaging nearby enemies, a crown that wards against psychic intrusion, etc. Any character could benefit from a bit of foresight and preparation along these lines.

A Githyanki horizon walker may be a better bet than you realize, they get resistance to psychic damage, theL11 distant strike ability allows a teleport 10 feet twice which gives you a way to both defeat a grapple and make an attack on the mindflayer(s) that tried to grapple. foe slayer is incredible when used properly - forget the damage 5 points max isn't going to add much but adding your wisdom bonus to the to hit is very powerful. Horizon walker's misty step  spell ability is another way to escape a grapple and Haste gives you 3 attacks a round with possibilities for more. Planar warrior makes all damage from one attack force damage while adding 2D8 damage to that on one attack.  If you can fit it in use the fighting initiate feat to take great weapon fighting and then another feat (or two) for great weapon master and PAM. then there is a public homebrew weapon: Llaw's Halberd  that is a +2 weapon that does radiant damage and an additional 2D6 damage to aberrations.you would want to take deft explorer and Favored enemy to choose abbrrations. 

Here is an example: https://www.dndbeyond.com/sheet-pdfs/wcwilson82355_100004920.pdf