The Expand mode of FabFilters Pro-MB can be super useful. Especially the downward expension (setting the range to a negative value) in combination with a pretty high attack value that lets the attack unaffected. Would be neat to see this functionality in the Quad Cortex for more studio like processing. This feature could be integrated into the Multiband Compressor that is mentioned in an other request with a lot of votes, but I want to highlight the expand functionality, plus it could possibly be added with a second update later on after the MB Compressor has been introduced.