2018-09-03
You can't {T} a creature that hasn't been under its controller's control since that player's last upkeep.
2018-09-03
You can't sacrifice permanents you don't control.
2018-09-03
Each permanent can only activate one loyalty ability per turn, no matter who activated it.
2018-09-03
Effects such as The Chain Veil and Teferi, Temporal Archmage's emblem that affect planeswalkers you control won't allow you to activate multiple abilities of a planeswalker you don't control.