Humanoid Cows
Okayu Humanoid Cat Easter Egg
If you nametag a Humanoid Cat with "Okayu", you'll get the Nekomata Okayu's variant.
Queen Cat's Inventory
If you Shift + Right Click your tamed Kemomimi, it will open up their inventory.
Queen Bunny & Princess Bunny
Korone Humanoid Dog Easter Egg
If you nametag a Humanoid Dog with "Korone" you'll get Inugami Korone's variant.