I wish Revit had the ability to merge Line Styles, Line Patterns, Fill Patterns, Fill Types, etc. through the manage tab similar to the way you can merge layers in AutoCAD.
As a BIM manager who joined a massive project half way through, trying to reign in and keep these elements clean and conform to office standards is a nightmare. To the best of my knowledge, my only option is to delete the "illegal" patterns and have the team help spot areas that have gone blank or regressed to default. If I were able to fold the "illegal" elements into the correct ones, the task would be far less painless.
(Also the ability to purge fill patterns would go hand in hand with this).

I apologize if this has been wished for before, I didn't see any mention of it though.

THANKS!