Animals available for thse 2 abilities are really up to your imagination. There are many beasts in Season Unending with established stat blocks, but these entries could consist of any medium or small sized real-world animal. This is the list as it stands:
@Kwama Worker , @Kwama Warrior , @Sabre Cat , @Mountain Lion , @Mudcrab , @Skeever , @Wolf , @Bear , @Horker @Lion , @Ash Hopper . You may also flavor your conjuration as any real-world non-extinct animal that would typically weigh 500 pounds or less.
This is your list of options for reatures you can conjure using the Conjure Undead spell. The list excludes any undead that are technically Tanaari Daedra.
@Zombie , @Wight , @Mummy , @Shadow , @Shade , @Dwarven Spectre , @Ghost , @Draugr , @Draugr Wight , @Restless Draugr , @Skeleton , @Wraith , @Death Hound , @Bonewalker , @Ra-Netu , @Ancestor Ghost , @Bog Blight , @Bonewolf , @Bloodfiend , @Flameskull , @Poltergeist , @Banshee .
This is your list of options for creatures you can conjure with the Conjure Tanaari and Summon Tanaari spells:
@Clannfear , @Ogrim , @Maldrith , @Vermai , @Mind-Shriven , @Mistman , @Shambles , @Wrathman , @Boneman , @Banekin , @Scamp , @Imp .
This is your list of options for creatures you can conjure with the Conjure Dremora and Summon Dremora spells:
@Spiderkith , @Omen , @Xivkyn , @Winged Twilight , @Xivilai , @Nocturnal Shrike , @Mazkyn , @Aureal , @Skaafin Warrior , @Spider Daedra , @Huntsman , @Grievous Twilight , @Gloam Knight , @Meridian Guardian , @Harvester , @Doppelganger , @Auroran , @Kyn Warrrior , @Venomkith .
This is your list of options for creatures you can conjure with the Conjure Atronach Spell:
@Flame Auranoch , @Frost Auranoch , @Storm Auranoch , @Flame Atronach , @Frost Atronach , @Storm Atronach , @Water Auranoch , @Water Atronach , @Stone Atronach , @Cold-Flame Atronach .