I think in the EA there are only animals that currently are present as wildlife or because of the intro/tutorial :
- Imps (Nautiloid Attack)
- Boars (druid cove NPC + Astarion's "friend")
- Ravens (various slaughter sceneries, probably sharing same animation rigs than birds)
- Rats (druids cove, cellars, etc. very easy since barely anything to animate/model)
- Wolfs (Giant wolf as druid companions)
- Bears (same)
- Frog (like the swamp one)
- Spider (basically a reduced version of giant ones, not too hard to do)
Others familiars that seem "unique" to the player :
- Crabs (same, didnt find them near sand beaches, maybe they are)
- Cats (probably easy to model and rig, same effect as minor illusion)
- Quasit (probably the most elaborate amonst familiars)
So basically Larian didnt include all animal companions YET, it most probably was easier to only include animals that were needed for the story and world, for starter.
I have no doubt every available animal companion in the 5e ed. will be included in the final release. And if you dont have wanted color, I'm pretty sure there will be mods for that too...
