The feature is still there but it doesn't return all results like it did in older version of Office. 2016 had a nasty bug that made the Advanced Find window "disappear" (resized itself to a tiny sliver and unless you know the ALT-SPACE shortcut to get to Resize the window is just lost). I don't know if that but persisted into newer versions. Microsoft acknowledged the bug but said they were de-emphasizing Advanced Find in favor of the awful search in the main Outlook window.
In Outlook 2010 I could do a search for all messages from a given sender with specific words in the subject and an attachment of at least 100KB and get results.
In Outlook 2010 I could do a search for all messages from a given sender with specific words in the subject and an attachment of at least 100KB and get results.