The best alternatives to Squarelink are HitPay, Inscribe, and PayStand. If these 3 options don't work for you, we've listed a few more alternatives below.
Inscribe is an open protocol allowing anyone to “inscribe” rich metadata on ERC721 NFTs. We’re starting with verified signatures, so you can create memorabilia signed by your favourite influencer, or a digital collection of cool folks you've met!