cargodog on Nostr: Yeah, is awesome. I use it daily. But, I'm looking for a general sign/verify tool ...

Yeah, is awesome. I use it daily. But, I'm looking for a general sign/verify tool suite using my Nostr ID. I guess it's really the "transmitted through relays" part of Nostr that I'd like to challenge. What if I want to sign notes and stuff transmitted via email or github releases or posted on forums or Bitcoin blocks, etc.