Under $10: Cryptbreaker, Zombie Master (if you're adding Urborg, Tomb of Yawgmoth), Balthor the Defiled, Crypt Ghast, Graveborn Muse, Grimgrin, Corpse-Born, Living Death, Dimir Signet, Beseech the Queen Pricey stuff: Sidisi, Undead Vizier, Relentless Dead, Lord of the Undead, The Scarab God, Mikaeus, the Unhallowed, Phyrexian Altar, Yawgmoth's Will, Vampiric Tutor, Demonic Tutor, Intuition, Cyclonic Rift, Tombstone Stairwell, dual lands, fetches, you know the stuff If you want to enhance your finisher potential even further, then adding Phyrexian Altar makes your Gravecrawler combos much more powerful, but that's a $70 investment
These are cards that could mechanically exist in Magics existing rules framework, and could be printed into a black-bordered set
Not so bad in a Bloomburrow Draft and other MTG formats where you can run multiples, but Commander limits you a bit
Plus, with a few more meta-friendly upgrades, this starter deck could go toe-to-toe with some constructed decks
Requiring players to manage both aggression and disruption, Tempo tests a lot of the key skills in MTG arguably further than even Control
It also has the and lowest and almost the fewest reviews, suggesting fewer copies were sold overall