If your opponent overextends, Be Prepared can dramatically set them back and give you the opportunity to catch up
It's Legendary because if it wasn't it would be completely broken
This works specifically, whenever you cast instants or spells on a creature you control, allowing you to exile the card after resolving it, instead of putting it in your graveyard to then be put back into your hand on the next end step
Skullclamp There's also some less obvious candidates, like Reveillark's trigger is doubled if it's triggered by dying, and possibly other cards that out there that don't specifically mention creatures dying but still count
Upgrading SOS Commander Decks These Secrets of Strixhaven Commander decks are strong out of the box, but this guide shows how to level them up fast
Since Esper Sentinel has a base power of 1 and the current power is 3, Sovereign Okinec Ahau attacks and places two +1/+1 counters on Esper Sentinel