https://gitlab.com/surfsara/email2trac allows updating Trac tickets from email replies. (I have not used it, but I know it's actively maintained.)

The default Trac search is very simple, sometimes maybe too simple. There's also the Ticket Query UI for field-based searching, which I use very often and quite like. Plugins for using solr or whoosh search engines also exist, but I haven't used them and don't know much about them.

I also recommend the auto-completion plugin: https://trac-hacks.org/wiki/WikiAutoCompletePlugin