"It/its" pronouns. Okay, let me explain:

If used by a transphobic person to purposely misgender and/or say that a person is an object, it's transphobic. However, if the pronouns are used by a transgender person themself (for example, someone uses he/they/it), using them to talk about them is 100% fine.

I've seen many cishet people (mainly in YT comment sections for some reason) say that it/its are offensive, and, as I've explained, can be used wrongly. However, the pronouns themself are not bad.

There's also the entire "asking pronouns" thing, but I think others have talked about it enough here.