To put it simply, it'd be nice to be able to delete posts. The reason that comes to mind is double-posts, which happens when somebody accidentally posts the same thing twice in a row.

i sponsor this!

Ame up before, agree.

It could also be useful for, like, people who post in do-not-post galleries and such (not targeting anyone specifically)

The only problem is that every post you make becomes a link, and has a certain ID. If someone else posts on any thread after you post, then... yeah

Just to clarify, are you talking about the post # that appears on the top right hand corner of each post? Like if person A makes post 2 and person B makes post 3 then person A deletes their post, the post #s become 1, 3, 4 ...?

I guess to solve this, you can either just go with the wrong ordering (though this might really bug some ocd people) since this would prevent the links from being messed up (since links just involve the page number and the post number).
Another possibility is to only allow the deleting before another person posts below you. This would solve both the ordering and link problem as well as avoiding accidental deletes in the middle of a thread and now there's a gap in the conversation (if that makes sense).

Adding to this idea, I also think it'd be really useful to delete threads that you make since currently, you'd need to ping Krin or Faiona to get that done (I think, I've never done it).

Yep, I am. And yes, that would bug me -.-

But maybe Krin and Fai could do this forum revamp thing where they delete all the locked threads(except official) unless you dont want it To be deleted? Idk, really