Those that follow the Fiend get an imp or a quasit, depending on inclination. Those who pact with the Archfey get a pseudodragon or a sprite.
What do the insane few that pledge their soul in service of a Great Old One receive? Nothing. Nada. Bupkis. Until now.
Featured here are the Gibbering Orblet, Albino Penguin, and Flumphling, all well-suited to being forms that any warlock's chain pact familiar could take, but tailor-made for warlocks that follow a Great Old One.
- Gibbering Orblet - Gibbering (save vs disadvantage on attacks), Poison Spittle (ranged attack w/ save vs poison), Phasing (automatic disadvantage on attacks vs orblet, can take no actions)
- Albino Penguin - Blindsight (great for shared senses / seeing through illusions), Swim Speed, Fear (as a Quasit)
- Flumphling - Advanced Telepathy (can hear others' telepathy), Telepathic Shroud (cannot detect its or master's thoughts w/o consent), Tendrils (weak melee w/ weak damage-over-time), Stench Spray (save vs stink, poison with AoE potential)
- Gibbering Orblet may be leaning a bit strong, and Albino Penguin may be a bit weak comparatively. This is roughly okay (but not ideal), though, as the familiars presented in core materials don't have anything approaching balance with one another.
- Lack of Magic Resist sidebar - As per what a tweet from Mike Mearls says, warlocks are not intended to get their familiar's Magic Resistance despite the text in the familiar sidebars (i.e. the imp's sidebar on page 69 of the MM). I have not included the sidebars here to conserve room, but you can assume similar sidebars exist for the Albino Penguin and Flumphling.
- My grasp of monster math is still pretty sketchy, but some people on reddit at least prodded me in the right direction.
Link to the reddit thread.