Make your own mod:
WARNING: the bloons td x 1.5 source code is basically unusable due to how old and poorly coded it was. For some reason the 1.4 version of the source code seems mostly stable.
Maw Mod (by WillMAW2) (Updated: 1/19/24):
Bloons TDXpansion (by LuigiKirby):
Carl Mod (by CarlFilip19) (Updated: 7/29/21):
Carl x Maw Mod (by CarlFilip19/Maw) (Updated: 7/31/21):
Cryo Mod (by Cryo):
Rubber Mod (by Rubber):