MS Visual Studio has a great feature: it automatically suggests the units to add in using
clause when you typing the code with refrences to absent standard classes.
This is not a tool to suggest references, it only cleans up unneeded unit clauses.
CnPack IDE Wizards is an excellent opensource plugin for Delphi.
http://www.cnpack.org/index.php?lang=en
I use its Uses cleaner
feature a lot.
There is a menu item:
CnPack->Project Enhancements->Use Unit
I think this can be helpful for your needs.