Since you need to trash a card for this effect, choose a card you are unlikely to play, with Diable Jambe often being a suitable candidate
The impact of any one card in a commander deck is very hard to measure
Metalworker Metalworkers an artifact-matters creature that can effortlessly tap for upwards of 6-10 mana
2-Mana Looters Wizards of the Coast has really been pushing the power level of 2-mana looters these days, with creatures like Kitsa, Otterball Elite, Malcolm, Alluring Scoundrel, and Duelist of the Mind all standing out as creatures that can filter through cards while pressuring your opponents
May include Mythic Rares from Shards of Alara to the most current Magic The Gathering (MTG) release
Just an incredible card for card advantage and flexibility and for thinning out the deck, and opened up a ton of different deck design options because of it