Countless people in YouTube often seem to think that mini-slimes are cute, so why not a mod that allows for tameable slimes?
Only small slimes can be tamed, the main item you use is gunpowder. However, it takes quite a great deal of gunpowder.
Mini-magmacubes can be tamed too, but unlike slimes, they require blaze powder.
Slimes are cute, but every night when the moon is full, they have a chance of changing into a big slime, which will be thoroughly aggressive. Unlike wolves, a slime will never attack other mobs, including other slimes. It will merely just keep pushing into you.