Some creatures like Agent of Treachery are bad enough when you get hit by their ETB once, but you can easily use them again and again while also jumping ahead on lands to drop other powerful cards
Self-Destruct Oh, Gilgamesh, you will always be remembered as a hero
While it requires you to track and remember specific things each turn in order to resolve the trigger in the end step, it does remove the need to disrupt the middle of someones turn to announce triggers in the manner required by cards such as Rhystic Study or Smothering Tithe
Summary Shiftable characters in Lorcana help you get strong characters for cheaper costs, paving the way for power players
Espers to Magicite exiles all enemy graveyards and lets you copy one of the creatures within them
Once Oblivious Bookworm's ability begins to resolve, it's too late to put any permanents onto the battlefield face down under your control or turn any permanents face up to prevent yourself from having to discard a card if you choose to draw a card