With the introduction of War of the Spark, Modern Horizons and Modern Horizons 2 a lot of those players either quit, started playing edh only or started playing one of the four strategies that were the best in my area (UW Control due to Teferi, Time Raveler, Jund due to Ragavan, Nimble Pilferer, Archon Reanimator Decks and four/five colour Omnath Decks)
Using all of the cards listed above, you can steal many permanents over the course of the game to trigger Agent of Treacherys second ability and draw three cards during your end step
Cards such as Cyclonic Rift, for example
Maybe it was a powerful some one or some thing
Many Allies have triggered abilities (especially ones with the rally ability), allowing them to double up on the triggers so long as Katara is on the battlefield
This practice began with Strixhavens Mystical Archive, a collection of iconic sorceries and instants sporting a gilded scroll style