Here are a list of animals that should be turned into blockland vehicles.
Wolf: You can ride on its back maybe make it move its paws.
Bear: Hmm... quite a tuffy maybe you could ride on its head lol and same thing with wolf.
Kangaroo: Should be able to ride in a little pouch like a joey, Lets you jump just a little higher than no jet player.
Fish: You could hold onto it and make it so it can only be held onto and ridden in water. Cause fish can't breath outta water.
Deer: Make a deer to ride on its back make it bend its head or something idk.
Thats all most of this might be able to be done in v11 though if anyone takes this suggestion as a topic to script and mod as.
Ps: Kaje gave me the idea check his Autumn Pond map