If you see "Mint First" when you go to mint from a collection, you have the opportunity to bring another creator's collection onchain and earn rewards at the same time.

First Minters will receive a portion of the Mint Fee for the NFT (the "First Minter Reward") for finding great editions and bringing them onchain for the world to mint. This is a part of the Rewards offered on Zora smart contracts. Specifically, First Minters shall receive 0.000111 ETH mint fee for each NFT minted from an edition they were the First Minter for.