mounts for more biomes

Savanna - Ostrich
-It can sprint faster than a horse for a short period of time then rest
-Can’t jump very high, easily frightened by creepers and thunder
-great combo with spear zombie

Badlands - vulture
-fly with high speed
-versatile and perfect for narrow places like caves
-deadly combo with spear zombie
-It could be nerfed as a bee for birch forest

Swamp - Frog
-It can swallow a mob or block and move it freely even a double chest full of items
-it can use its tongue as grappling hook
-it can attack with its tongue dealing stun effect
-Mega jump 
-Maybe it's a basalt deltas mob to balance it

Dark oak forest - invisible spider
-Climbs walls, ceilings and walks vertically
-Ability: goes invisible for a period of time
-Throws web blocks
-low health