Mind players, beholders, and aboleths oh my.

[Empyreal Dragon]

Trying to compile a full list of all variants of illithids, beholder, and aboleths, as well as all related stuff to them.

Magic items,

Related monsters,

Prestige classes. Anything

[Thurbane]

Hoo-boy, I love compiling lists, but that'll be a task and a half!

I'll update this post as I get the chance.

ABOLETHS

Monsters:
Shaboath (LoM)
Skum (MM1 (http://www.d20srd.org/srd/monsters/skum.htm))
Skum Renegade (online (http://archive.wizards.com/default.asp?x=dnd/psb/20030523e))

Items:
Aboleth Mucus (SS)
Aboleth Oil (poison) (A&EG)

Spells:
Aboleth Slime (online (http://archive.wizards.com/default.asp?x=dnd/oa/20061017a))

BEHOLDERS

Monsters:
Beholder (MM1)
Beholder, Bleeder (Dragon Compendium)
Beholder, Death Tyrant (FRCS)
Beholder, Gauth (MM1)
Beholderkin, Death Kiss (MoF)
Beholderkin, Director (LoM)
Beholderkin, Eye of the Deep )LoM)
Beholderkin, Eyeball (MoF)
Beholderkin, Eyeball, Swarm (EtU)
Beholderkin, Gouger (MoF)
Beholderkin, Hive Mother (LoM)
Beholderkin, Overseer (LoM)
Beholderkin, Spectator (LoM)
Gas Spore (LoM)
Gibbering Orb (ELH (https://www.d20srd.org/srd/epic/monsters/gibberingOrb.htm))
Half-Farspawn Beholder (sample Half-farspawn Beholder) (online (http://archive.wizards.com/default.asp?x=dnd/eo/20070810a))
Lurking Strangler (MM3)
Mindwitness (sample Half-illithid Beholder) (Und)
Phantom Beholder (sample Phantom Beholder) (online (http://archive.wizards.com/default.asp?x=dnd/eo/20070810a))
Stormstalk (MoE)
Vampire Beholder (sample Monstrous Vampire Beholder) (online (http://archive.wizards.com/default.asp?x=dnd/eo/20070810a))

Classes/PrCs:
Beholder Mage (LoM)
Eye of the Xanathar (online (http://archive.wizards.com/default.asp?x=dnd/prc/20061107b))
Fleshwarper (Secret of the Beholder) (LoM)
Ocular Adept (F&P)

Feats:
Agile Tyrant (LoM)
Bane of the Unclean (LoM)
Disintegration Finesse (LoM)
Disjunction Ray (LoM)
Focused Antimagic (LoM)
Graft Flesh (LoM)
Metaray (LoM)
Ocular Spell (LoM)
Thrall Bred (LoM)

Items:
Beholder Crown (MIC)
Crown of Eyes (graft) (FF)
Eye Stalk (graft) (FF)
Gazing Eye (graft) (FF)
Golden Beholder (Dragon Compendium)
Ocular (armor ability) (CoR)
Plated Skin (graft) (FF)
Replacement Eye (graft) (FF)
Third Eye (graft) (FF)

Spells:
Dreaded Form of the Eye Tyrant (CM)
Eye of the Beholder (BoVD)

MIND FLAYERS

Monsters:
Brain Golem (FF)
Dragon, Brainstealer (Dragon 337)
Elder Brain (LoM)
Half-illithid (template) (FF / Underdark)
Illithidae, Embrac (LoM)
Illithidae, Kigrid (LoM)
Illithidae, Saltor (LoM)
Illithocyte (LoM)
Madcrafter of Thoon (MM5)
Mind Flayer (Illithid) (MM1)
Mind Flayer, Alhoon (LoM)
Mind Flayer, Thoon Disciple (MM5)
Mind Flayer, Ulitharid (LoM)
Mind Flayer, Vampire (LoM)
Mind Worm (Dragon 337)
Mindwitness (sample Half-illithid Beholder) (Und)
Nerve Swimmers (Dragon 337)
Ogre Guard Thrall (MM4)
Purple Worm (MM1 (http://www.d20srd.org/srd/monsters/purpleWorm.htm)) [A&EG has rules for Illithids using them as mounts]
Shadow Flayer (MM5)
Thoon Elder Brain (MM5)
Thoon Hulk (MM5)
Thoon Inflitrator (MM5)
Thoon Thrall (MM5)
Urophion (LoM)
Ustilagor (Dragon 337)
Voidmind (template) (MM3)

Classes/PrCs:
Flayerspawn Psychic (CPsi)
Illithid Savant (SS)
Illithid Slayer (EPH)
Illithid Body Tamer (Und)

Feats:
Graft Flesh (LoM)
Graft Illithid Flesh (Und)
Illithid Blast (CPsi)
Illithid Bloodline (Dragon Compendium)
Illithid Compulsion (CPsi)
Illithid Enthusiast (CPsi)
Illithid Extraction (CPsi)
Illithid Grapple (CPsi)
Illithid Heritage (CPsi)
Illithid Legacy (CPsi)
Illithid Legacy, Greater (CPsi)
Mind Weapon (Dragon Compendium)

Items:
Antennae Graft (graft) (FF)
Brainmate (graft) (Und)
Climbing Legs (graft) (FF)
Extracting Tentacle (graft) (Und)
Eye of the Druuthbane (MoF)
Goring Horn (graft) (FF)
Grabbing Tentacle (graft) (Und)
Grasping Mandibles (graft) (FF)
Hauling Back (graft) (FF)
Humanoid Skin (graft) (Und)
Illithid Mindscorch (poison) (DotU)
Raking Tentacle (graft) (FF)
Rending Claw (graft) (FF)
Weapon Graft (graft) (FF)

Spells:
Flaying Tendrils (CM)

[Buufreak]

Never a list this complete without the Mind Witness.

[ShurikVch]

ABOLETHS

Monsters:
Aboleth (MM1)
Amphibious Aboleth (LoM)
Aboleth Mage (MM1)
Aboleth, Psionic (XPH)
Stygian Aboleth (LoM)
Uobilyth (Aerial Aboleth) (LoM)
Voice of Dagon (https://web.archive.org/web/20090924052103/http://www.wizards.com/default.asp?x=dnd/duad/20071207) (Half-Farspawn Aboleth) (Dungeon #152)

Classes/PrCs:
Savant Aboleth

Feats:
Craft Aboleth Glyph (LoM)
Death Frenzy (LoM)
Enlarge Mucus Cloud (LoM)
Graft Flesh (LoM)
Memory Eater (LoM)
Powerful Bite (LoM)
Quickslime (LoM)
Reach Bite (LoM)
Thicken Mucus (LoM)
Toxic Mucus (LoM)

Items:
Aboleth Tentacle (graft) (FF)
Amphibious Skin (graft) (LoM)
Inksac (graft) (LoM)
Mucus Projector (graft) (LoM)
Mucus Sheath (graft) (FF)
Skum Eyes (graft) (FF)
Skum Tail (graft) (FF)
Waterjet (graft) (LoM)

Spells:
Aboleth Curse (Storm)


In addition...

BEHOLDERS

Monsters:
Beholder Lich (D&D Miniatures: Unhallowed set)
Doomsphere (Monsters of Faerûn)
Elder Orb (LoM)
Beholder, Occultipus (Dangerous Denizens: The Monsters of Tellene)
Beholder Machine (Dungeon #90)

Classes/PrCs:
Ocular Master (Dragon #313)
Sphere Minion (Dragon #296)
Unholy Abomination (Dragon #313) - printed in the part about Beholders, but may work for any Aberration with Su 3+/day

Feats:
Maw of Power (Dragon #313)
Nimble Flier (Dragon #313)
Power Soar (Dragon #313)
Power Surge (Dragon #313)
Skilled Telekinetic (LoM)
Tentacular Stalk (Dragon #313)
Versatile Tyrant (Dragon #313)

Items:
Beholder Globe (Dragon #331)
Dimensional Pocket (Dragon #313)
Eye of the Beholder (Dragon #340)
Eye Tyrant Lens (Dragon #313)
Lens of Ray Chaining (LoM)
Lens of Ray Doubling (LoM)
Lens of Ray Extending (LoM)
Lens of Ray Widening (LoM)
Mouthpick Weapon (LoM)
Ocular Gems (Dragon #313)
Orb Armor (Dragon #313)
Sphere Mirror (LoM)
Suspension Sphere (Dragon #313)

MIND FLAYERS

Monsters:
Evolved Illithid Forlorn Husk (Sinister Spire)
Gibbering Terror (Dangerous Denizens: The Monsters of Tellene) - not, exactly, a Mind Flayer, but the "transformed ex-Human with tentacles for mouth" is very suggesting...
Half-Fiend, Glabrezu/Mind Flayer (http://archive.wizards.com/default.asp?x=dnd/we/20060630x&page=2)
Larval Flayer (Dragon #318/CPsi)
Mind Flyer, Psionic (XPH)
Mind Flayer Servitor (Dangerous Denizens: The Monsters of Tellene)
Neothelid (XPH)
Psionic Elder Brain (LoM)
Paragon Mind Flayer (ELH)
Shuluth (Weapons of Legacy)
Thoon Disciple (MM5)
Yaggol (Bestiary Of Krynn, Revised) - almost a Mind Flayer with name filed off; cmae in two variants - "Savage" and "Elite"

Classes/PrCs:
Illithidkin (Dragon #296)
Mind Flayer (Savage Species)
Mind Mage (Dragon #313)

Feats:
Agitated Causticity (Dragon #313)
Astral Fire (Dragon #313)
Bioelectrical Surge (Dragon #313)
Bull Blast (Dragon #313)
Concussive Blast (Dragon #313)
Dual‐Plane Summons (Dragon #313)
Energy Flare (Dragon #313)
Harden Energy (Dragon #313)
Solid Freeze (Dragon #313)

Items:
Backwatcher Carapace (symbiont) (Dragon #308)
Dimensional Tracking Net (Dragon #308)
Extractor Globe (Dragon #308)
Extractor Shuriken (Dragon #308)
Fastbreak Carapace (symbiont) (Dragon #308)
Hardy Carapace (symbiont) (Dragon #308)
Mnemonicus (symbiont) (Dragon #308)
Silent Carapace (symbiont) (Dragon #308)
Slippery Carapace (symbiont) (Dragon #308)
Strongarm Carapace (symbiont) (Dragon #308)
Tentacle Hooks (Dragon #308)
Tentacle Net (Dragon #308)
Wriggler (symbiont) (Dragon #308)

[Thurbane]

@ OP: Are you open to 3rd party and home-brew as well? Because that opens up more options.

Enworld Creature Catalogue (fan made conversions of 1E and 2E monsters):

Aboleth, Grand (https://web.archive.org/web/20110811203639/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=1653)
Aboleth, Greater (https://web.archive.org/web/20110811203759/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=1652)
Aboleth, Noble (https://web.archive.org/web/20110811203807/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=1651)
Aboleth, Ruler (https://web.archive.org/web/20110811203820/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=1650)
Aboleth, Saltwater (https://web.archive.org/web/20110811204039/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=1649)
Beholder, Kasharin (https://web.archive.org/web/20120915015256/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=1426)
Beholder-Kin (Examiner) (https://web.archive.org/web/20110811205132/http://creaturecatalog.enworld.org/cc/converted/aberration/beholder/examiner.htm)
Beholder-Kin (Lensman) (https://web.archive.org/web/20110811204857/http://creaturecatalog.enworld.org/cc/converted/aberration/beholder/lensman.htm)
Beholder-Kin (Watcher) (https://web.archive.org/web/20110223010635/http://creaturecatalog.enworld.org/cc/converted/aberration/beholder/watcher.htm)
Beholder-kin, Searechter (Marine Spectator) (https://web.archive.org/web/20120820022326/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=466)
Illithidae (template) (https://web.archive.org/web/20120515173607/http://creaturecatalog.enworld.org/cc/converted/view_t.php?TemplateID=23)
Illithidae, Cessirid (https://web.archive.org/web/20120930095245/http://creaturecatalog.enworld.org/cc/converted/view_c.php?CreatureID=677)