I am building a Commander deck with Muldrotha, the Gravetide as the Commander. During my deckbuilding, I remembered there is such a thing as a "Tribal" card type. Is Tribal one of the supported card types that can be cast from the graveyard using Muldrotha's ability?
From the comprehensive rules:
110.4. There are five permanent types: artifact, creature, enchantment, land, and planeswalker.
300.1. The card types are artifact, conspiracy, creature, enchantment, instant, land, phenomenon, plane, planeswalker, scheme, sorcery, tribal, and vanguard.
No, Tribal is not a permanent type.
From the Comprehensive Rules, Section 110:
110.4. There are five permanent types: artifact, creature, enchantment, land, and planeswalker. Instant and sorcery cards can’t enter the battlefield and thus can’t be permanents. Some tribal cards can enter the battlefield and some can’t, depending on their other card types. See section 3, “Card Types.”