I've compiled a list of all the unused/hidden anims present in the anim files. While there may be more models in the models bars, these are all the ones that you can see in the editor when you look at a unit's animation. This does not cover all unused models.
Most of these may already be popular, such as the fire giant's melee attack, and the sphinx's teleport, but there are other less popular ones too. Here it is:
Units :
Virtually all air units have a flail animation. I could be wrong, but from what I've researched there is no need for the animation in the game. Vortex maybe?
Anubite/Theris: JumpTakeOff, JumpLand, Run
Ajax (Hero): Run
*Some of the run anims are different from the walk ones, and some have no difference at all.
Arkantos (uber): Birth
Avenger: AttackB (the only one of its kind)
Axeman: Run
Bireme: WalkAttack
*Alot of ships seem to have a walk attack.
Brokk: Build x2 (two animations of build)
Dragon Ship: WalkAttack
Dwarf: Build, Run
Eitri: Build
Fenris Wolf/Ornlu: Run
Filbumwinter wolf: WalkAttack, Run
Fire Giant: Attack (different from RangedAttack, usually means a melee)
Fire Siphon: Attack
Gargarensis: Run
Hippocampus: Attack (i was surprised by this one, one of the less popular ones i beilieve)
Hoplite: Run
Juggernaut: WalkAttack
Krios: Attack, Recover
Kronos: Flail
Oracle Hero: Recover
Osiris: Charging
Petsuchos: Attack, RangedAttack
Pharoah: Attack, Build, Convert
Pharoah 2nd: Same as above
Polaris: Run
Priest: Attack
Prisoner: Same as villagers, Run
Sea Snake: Run
Serpent: Run
Skareling: Build
Skult: Attack
Slinger: Run
Son of Osiris: Build
Son of Osiris XP: Same as above
Spearman: Run
Sphinx: TeleportIn, TeleportOut
Spider: Death, Pickup
Theocrat: Attack, Recover
Trireme: WalkAttack
Villager Egyptian: Pray
Villager Norse: Build
Wadjet: Run, WalkAttack
Walking Woods, all with the exception of Oak, Marsh, and Tundra: Run
War Barge: WalkAttack
Embellishment
Boar Ajax: Run
Boar Arkantos: Run
Boulder Rolling, all except Boulder Rolling Dead: Walk
Folstag Flag: Death
Gate Ram: Attack
Gate Ram 2: Attack
Golden Lion: Run
Locust Swarm: Walk, Attack, WalkAttack (one or two of those)
Tornado: Walk, Attack
Nature :
Bear: Run
Caribou: Run
Cow: Run
Crocodile/of Set: Run
Crowned Crane: Run
Deer: Run x2
Elk: Run x2
Gaia Forest Tree: Flail
Gazelle/of Set: Run
Giraffe/of Set: Run
Harpy: Attack
Hyena/of Set: Run
Lion: Run
Marsh tree: Flail
Polar Bear: Run
Rhinoceros/of Set: Run
Tree Oak: Flail
Tree Oak Burning: Flail
Tree Oak Autumn: Flail
Tree Palm: Flail
Tree Palm Burning: Flail
Tree Pine Snow: Flail
Tree Pine Snow Burning: Flail
Tundra Tree: Flail
Tundra tree Burning: Flail
Vulture: Walk
Walrus: Run
Water Buffalo: Run
Wolf: Run
Wolf Artic: Run
Wolf Artic 2: Run
Misc :
Battle Boar: Cinematic (this is here because I personally don't remember this being used in the campaigns)
Bella: No birth animation, maybe they just didn't care
Kataskopos (scout): 3 extra and seemingly unecessary anims of each anim category.
Kraken: Unused texture, as far as I know. I believe there was a mod that included this in it.
Murmillo: Cinematic (it exists, you just don't see a visual)
Nemean Lion: Same as battle boar
There are many of these which may actually be used in some way, but just unexpected. For example, the tree flail animation may happen when a torndao comes through (before it falls). I haven't done enough research though.
Most of these may already be popular, such as the fire giant's melee attack, and the sphinx's teleport, but there are other less popular ones too. Here it is:
Virtually all air units have a flail animation. I could be wrong, but from what I've researched there is no need for the animation in the game. Vortex maybe?
Anubite/Theris: JumpTakeOff, JumpLand, Run
Ajax (Hero): Run
*Some of the run anims are different from the walk ones, and some have no difference at all.
Arkantos (uber): Birth
Avenger: AttackB (the only one of its kind)
Axeman: Run
Bireme: WalkAttack
*Alot of ships seem to have a walk attack.
Brokk: Build x2 (two animations of build)
Dragon Ship: WalkAttack
Dwarf: Build, Run
Eitri: Build
Fenris Wolf/Ornlu: Run
Filbumwinter wolf: WalkAttack, Run
Fire Giant: Attack (different from RangedAttack, usually means a melee)
Fire Siphon: Attack
Gargarensis: Run
Hippocampus: Attack (i was surprised by this one, one of the less popular ones i beilieve)
Hoplite: Run
Juggernaut: WalkAttack
Krios: Attack, Recover
Kronos: Flail
Oracle Hero: Recover
Osiris: Charging
Petsuchos: Attack, RangedAttack
Pharoah: Attack, Build, Convert
Pharoah 2nd: Same as above
Polaris: Run
Priest: Attack
Prisoner: Same as villagers, Run
Sea Snake: Run
Serpent: Run
Skareling: Build
Skult: Attack
Slinger: Run
Son of Osiris: Build
Son of Osiris XP: Same as above
Spearman: Run
Sphinx: TeleportIn, TeleportOut
Spider: Death, Pickup
Theocrat: Attack, Recover
Trireme: WalkAttack
Villager Egyptian: Pray
Villager Norse: Build
Wadjet: Run, WalkAttack
Walking Woods, all with the exception of Oak, Marsh, and Tundra: Run
War Barge: WalkAttack
Boar Ajax: Run
Boar Arkantos: Run
Boulder Rolling, all except Boulder Rolling Dead: Walk
Folstag Flag: Death
Gate Ram: Attack
Gate Ram 2: Attack
Golden Lion: Run
Locust Swarm: Walk, Attack, WalkAttack (one or two of those)
Tornado: Walk, Attack
Bear: Run
Caribou: Run
Cow: Run
Crocodile/of Set: Run
Crowned Crane: Run
Deer: Run x2
Elk: Run x2
Gaia Forest Tree: Flail
Gazelle/of Set: Run
Giraffe/of Set: Run
Harpy: Attack
Hyena/of Set: Run
Lion: Run
Marsh tree: Flail
Polar Bear: Run
Rhinoceros/of Set: Run
Tree Oak: Flail
Tree Oak Burning: Flail
Tree Oak Autumn: Flail
Tree Palm: Flail
Tree Palm Burning: Flail
Tree Pine Snow: Flail
Tree Pine Snow Burning: Flail
Tundra Tree: Flail
Tundra tree Burning: Flail
Vulture: Walk
Walrus: Run
Water Buffalo: Run
Wolf: Run
Wolf Artic: Run
Wolf Artic 2: Run
Battle Boar: Cinematic (this is here because I personally don't remember this being used in the campaigns)
Bella: No birth animation, maybe they just didn't care
Kataskopos (scout): 3 extra and seemingly unecessary anims of each anim category.
Kraken: Unused texture, as far as I know. I believe there was a mod that included this in it.
Murmillo: Cinematic (it exists, you just don't see a visual)
Nemean Lion: Same as battle boar
There are many of these which may actually be used in some way, but just unexpected. For example, the tree flail animation may happen when a torndao comes through (before it falls). I haven't done enough research though.
[This message has been edited by Thangbrand Aesirear (edited 03-21-2015 @ 05:46 PM).]