In 1998, there was a Japanese tournament called Kangaskhan Family Event, which pitted parent/child teams against one another
Freeze the characters your opponent was about to win with and buy yourself some time to banish them
It's the gold standard for buff balance against which many other instants are measured
Corey Burkhart's control course over on Spikes Academy also happens to have a full module on Legacy Control, so check that out if you want even more information
Most of its early- and mid-game cards like Paldean Wooper, Arbok, and Grifaiai poison your opponent's active Pokemon, with Grifaiai in particular being able to do so from the bench, while Paldean Clodsire ex does double damage if the opponent's active Pokmon is poisoned
simply gaining life and calling your deck a "life gain deck" isn't going to be good enough most of the time