While it isn't quite an ultra-staple like Sol Ring is, it is one of the 30-ish most played colorless cards in the format, showing up in all kinds of decks, including enters-the-battlefield focused decks
Edgar Markov (Serialized Double Rainbow Foil Movie Poster) Innistrad Remastered Market Price: $2,499.99 As we've seen with multiple lists before it, serialized Magic cards are worth a boatload
It's also legal in Legacy, Modern, and more
Ral's Vanguard Vanguard Requirement Your starting deck contains only instant, sorcery, and land cards
Tinybones, Bauble Burglar Its hard to make discard work in Commander because you have so many opponents
Bonehoard Dracosaur Bonehoard Dracosaur gives you extra cards to play each turn, which alone is pretty powerful