How 'bout
Confusion Balls? It's slightly tricky to do the confusion - and I'm not 100% sure you can make it work properly without mana - but could be fun!
Would be fun to have a
Bursting Ball that caused the unit to blow up like a balloon unless they backed off which would allow them to deflate a little. Too much pushing and POP! Yeah - ok... it's impossible to do this - but would be
funny to watch!
I could see an
Easter Egg Ball that dropped random items now and then as it was moved around, including satchels, pus, mortar rounds, etc. These could be very dangerous for the people near the ball (and could possible propel it) but could also be rewards for ghols and/or laying defenses.