Myriad Myriad is a returning mechanic that creates copies of your attacking creatures which enter tapped and attacking other, non-defending opponents
The dungeons you can choose here are Dungeon of the Mad Mage, Lost Mine of Phanelver, and Tomb of Annihilation if it has been a while since you interacted with that mechanic
Best of all
But when all of those archetypes are thrown together into the grand melting pot of Commander, a few top-tier choices stand out
3-6 Uncommon cards
(It is every creature type.) Number 132 Language English Legal Formats Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Pioneer, Timeless, Vintage Not Legal Formats Alchemy, Pauper, Standard Rulings (2/5/2021) Replacement effects that modify how creatures of a certain creature type enter the battlefield will apply after you apply the effect of Maskwood Nexus