I’m not sure about the other two, but T-Mobile has an unlimited data plan that is $40 a month for unlimited everything for a phone and $20 month unlimited for tablets if you have at least one phone on the plan. They don’t throttle you but they do prioritize your data over 50GB. I’ve never seen it happen.

But because you can’t just add more wires to the airwaves, there is a limited amount of bandwidth no matter what you do. So that’s fair.

They offer unlimited tethering still 512Kbps.