I have some tower ideas.
1) There’s a Supermonkey, so why not a Batmonkey or something like that.
2) Tank: Shoots slowly, but big range and goes back and forth from the spot it is placed in.
3) Poison Monkey: Shoots poisons darts, popping 1 layer of the Bloon it hits and pops other layers over-time.
4) Spear Monkey: This monkey has a spear and can pop up to 3 Bloons without upgrades.
5) Soldier Monkey: Shoots very fast, but with low range and, like the Tank, goes back and forth from the spot it is placed in.