They can be versatile answers as well as threats all in one
If a player casts a spell that targets multiple permanents their opponent controls with ward, each of those ward abilities will trigger
5 Elesh Norn, Grand Cenobite Elesh Norn is a legendary Phyrexian who appeared more recently in the March of the Machine set, though her original card is still the most famous among all praetor cards
To others, it's a dreadful experience watching your opponent play solitaire for what feels like eternity until either they win or fail to combo off, with no interaction on your part
Helga, Skittish Seer If you want to cast big creatures and draw cards, you could do worse than playing Helga in the command zone
The first is more effects like Psychomancer and Shard of the Void Dragon, both of which trigger off of artifacts being put into the graveyard