A combo deck without any other pain built into the mana base will appreciate an untapped green source, even if it comes at a cost
If a samurai or warrior attacks alone with Raiyuu out, that creature is untapped and players can get a second combat phase
Common failure modes include: Generating 83 or 94 cards and calling it a complete deck Including the commander in the 99 rather than the command zone Suggesting cards outside the commander's color identity Listing duplicate cards (violating singleton) Miscounting after you ask for changes ("replace X with Y" sometimes adds both) None of these are edge cases
Will you be getting this Secret Lair, and if so, which of the cards will you be building Commander decks around
Enters the battlefield tapped and can be tapped to produce either one black or one red mana
For example, you might combine Bolas's Citadel and Aetherflux Reservoir, giving you card advantage and life to offset the life loss, or maybe have reanimate loops using Chainer, Dementia Master and Gray Merchant of Asphodel