@ClaraJ99 It's not really possible.
This question is really about SharePoint and OneDrive, that's where all of Teams files live, and where a control would need to be applied. There is no simple block for particular file types however, you can prevent them syncing in OneDrive but not block browser uploads.
If you had E5 I guess you could use MCAS File rules to delete files of certain types.
Why do you want to?
