1 prefixes and postfixes are not a mass like item really, so if you like them, get them
We just like prefixes, so i, e, 247 and 1 are natural to us
I don't see i or e being a postfix but 1 can, it's just something we don't do
I don't know of any other company with as much prefix development as us, but, if you like it, it's not that bad
It's just development is a big cost today
So I doubt you'll find a buyer but it could be okay for development
You could probably register a bunch of nice 1 postfixes and if you learn how to develop yourself, who knows, you might build a brand
But stick to .com
Good luck