Fisher Yates - Solidity. Find more details on https://josuejulcarima.medium.com/fisher-yates-solidity-snippet-1ce656e63acc

fy.sol

    // fisher yates:
    mapping(uint256 => uint256) private _fyAlreadySeen; // defaults to zero, so stores indexes from 1

    function fyGetMapping(uint256 ridx) private view returns (uint256) {
        uint256 m = _fyAlreadySeen[ridx];
        if (m != 0) return m - 1;
        return ridx;
    }
    function fySetMapping(uint256 ridx, uint256 idx) private {
        _fyAlreadySeen[ridx] = idx + 1;
    }

    function mintOneNft() private {
        // getting a random number in the interval [totalSupply(); maxNfts>
        // where totalSupply() is the current amount of NFTs already minted
        uint256 ridx = _random(totalSupply(), maxNfts, totalSupply());
        uint256 tokenId = fyGetMapping(ridx);
        uint256 oldTokenId = fyGetMapping(totalSupply());
        
        fySetMapping(ridx, oldTokenId);

        _safeMint(msg.sender, tokenId);
    }

More docs: https://josuejulcarima.medium.com/fisher-yates-solidity-snippet-1ce656e63acc