I can't answer for ALL sanctioning bodies, but for USA softball there are only a few differences. Off the top of my head..
- The size of the ball (11" vs. 12")
- The pitching distance (35 feet)
- Can't wear metal cleats
Other organizations might have rules about stealing bases, not calling infield flies, or dropped third strikes. But those would be rules unique to their games only. There aren't universal rules that apply to all sanctions.