Take cards like Bone Shredder, Serrated Scorpion and Sling-Gang Lieutenant, mix them in with some sacrifice outlets like Deadly Dispute, Viscera Seer, and Bolass Citadel and youll have the makings of a Shirei deck
As you can see, this format has all of the mana you need but just one spell cast per turn, so only copying one per turn won't be a restriction, and getting the copies for free each turn is big value
4 Barbflare Gremlin Mana Burn Is Back Barbflare Gremlin offers two really good things
Put both cards onto the battlefield under your control, then shuffle
For example, even if we interpreted your library as part of the battlefield for this purpose, slipping one into the card sleeve of a card in your library during a search effectively marks your deck, and that's not allowed
Salvage Titan may be worth including as well, as it will almost always qualify for the alternate casting cost