Mastodon 4.2.0 brings a number of new options for searching. You can add special operators to filter what you search for:

has:media or poll or embed
language:fr or any two letter ISO language code
is:reply or sensitive
from:user or me (me is for your own posts)
in:all or library (library means posts you've interacted with)
before:date (YYYY-MM-DD)
during:date
after:date

Make sure there's no space after :

For example, to only show results with polls include the phrase has:poll in your search.