Perhaps Meow Meow Meow Tensei Shitara Slime Datta Ken (WN) Kumo Desu ga, Nani ka? I was a sword when I reincarnated Reincarnated as a Dragon’s Egg ～Lets Aim to Be the Strongest～ I reincarnated into a vending machine At the Northern Front Behemoths's Pet Dragon Life Invisible Dragon I know several BL with non human leads but don't know if you like BL. There are many more. You could also look on the tag non-humanoid protagonist.
Tales Of The World Devouring Serpent - serpent protagonist Strange Life of a Cat - just like the title of this novel, the male protagonist reincarnated as a cat. Game of the World Tree - mc is not human Elqueeness - water king spirit Little Phoenix Is Not An Immortal