Where might we have seen your work before
Raiyuu, Storms Edge If you specifically want to build around samurai as a creature type, Isshin, Two Heavens as One definitely works, though Raiyuu, Storm's Edge is friendlier on the budget
While this is not an option for everyone if you do decide to get into Pucatrade or selling on TCGPlayer you can save a lot of money by buying in bulk
You play Acererak, venture into the dungeon and put Acereraks bounce trigger on the stack, use Relic of Legends to tap Acererak for one black mana, and repeat
I dont see them getting substantially worse anytime soon, as they count as permanents and can help you cast cards before you should be able to in a game of Magic, as Garfield intended
Gravebreaker Lamia Even if Lamia dies before taking advantage of the second ability, this card does a ton of work