Dungeons of Death

Dungeons of Death is a 100-card Commander precon from Forgotten Realms Commander, released July 23, 2021. It is led by Sefris of the Hidden Ways, an Esper commander.

Sefris of the Hidden Ways

Whenever one or more creature cards are put into your graveyard from anywhere, venture into the dungeon. This ability triggers only once each turn. (To venture into the dungeon, enter the first room or advance to the next room.)
Create Undead — Whenever you complete a dungeon, return target creature card from your graveyard to the battlefield.

The list runs 39 lands and 33 creatures, and its nonland cards average 3.62 mana. At today's TCGplayer prices the whole deck's cards come to about $104.25, and the most valuable is Wand of Orcus at $12.26.