Complex Search Strings
Add the ability to enter multiple search variables in the search bar similar to how Outlook's search function is implemented. For example, in Outlook "[generic term] from:[person] hasattachment: [yes]" finds only messages containing the term from a specific person AND that have attachments.
This could be expanded in teams to look for specific file extensions, in certain teams/channel, etc. This would be faster and much more powerful than entering a search and then clicking on the 'filter' button where you are constrained to what is available in the drop down UI.
I surprised this isn't getting more votes, so maybe there's another one with the same idea. The example here of using from: and hasattachment: has come up in our discussions of trying to migrate from Skype for Business to Teams as well. Some have expressed that they often search by the person they know sent the message, so replicating that would be very helpful.