At my last company, when someone sent a solid bug report, made a good pull request to our docs, or asked for swag, I'd send them some gear with a handwritten no

At my last company, when someone sent a solid bug report, made a good pull request to our docs, or asked for swag, I'd send them some gear with a handwritten note and my card. People went crazy about the handwritten note and got thank you notes for the note! I think it was so different that it was a cool surprise.