If your commander itself is a source of card advantage, then you can get away with a lower number here
$0.39 Minister of Impediments Dissension $0.49 Timin, Youthful Geist Innistrad: Crimson Vow Commander Decks $0.79 Cone of Cold Commander Legends: Battle for Baldur's Gate $0.79 Dreamshackle Geist Innistrad: Crimson Vow $0.99 Hylda's Crown of Winter Wilds of Eldraine $0.35 Downpour 2013 Core Set $0.35 Sharae of Numbing Depths Wilds of Eldraine $0.35 Feeling of Dread Innistrad $2.29 Elvish Mariner The Lord of the Rings: Tales of Middle-earth $0.39 Blustersquall Return to Ravnica $3.99 Hylda of the Icy Crown Wilds of Eldraine $1.29 Verity Circle Ravnica Allegiance 0 results found
Crucible of Worlds was a fan generated card, and is getting pricey, so I could easily see that here
Undying and persist are both triggered abilities that leverage the graveyard and trigger when a creature with the respective ability dies
To make deck building easier, there's a cycle of cards at common that have two of the relevant creature types, as well as ten hybrid cards, one for each color pair
Activates from your Graveyard + Banishes from Graveyard for cost + and Banishes itself from Graveyard for cost + + Activation requirement +, Cost +, Effect + and Quick-like Effect + + + Destroys your opponent's Monster Cards + (ar) +, Vrana Krila (hr) +, Aile Noire (fr) + and (el) + +