List of free nft stuff for developerππ½
If you're looking for all programming tools around nft (not just free). Check this page List of nft Programming Tools

Tatum
Blockchain platform providing one API and SDK to create NFTs and access 40+ blockchains, including Bitcoin, Ethereum, Polygon, Algorand, Flow, and Celo.
Tag: blockchain, nft, web3, api
Unlimited API calls capped at 5 requests/second.

Unwonted
Unwonted is an in-browser tool to create generative art. Create rare NFTs using unwonted for free. It's safe and your images never leaves your computer.
Tag: NFT, AI