I lost my email!
That's a little more troublesome. But if you send a contact form with some identifying info, we might be able to help you out.

I, uh, might be a little bit banned?
You need to go to the ban appeal thread. This is not optional. No bans will be lifted without the user first discussing their ban. Creating any additional account while banned, for any reason, is strictly forbidden.
(Yes, not-banned users, we know, you can't see what's behind the above link. This is intentional.)

I got banned, discussed my ban, but they said no. I think that super sucks and I want to discuss it again.
First, consider whether you've actually learned from your ban and are capable of demonstrating this. If not, there's no point continuing.
But if you think you're really better, be aware that there is a one-year waiting period on reappeals. Yes, that is a long time. That is very much the point.
If it's been at least a year since your ban was last discussed, you can send a contact request asking to discuss it again. No guarantees on the outcome of the request, to be clear - if you're a jackass about it, we won't even discuss it. See point 1.