https://www.darktable.org/
Description from website:
darktable is an open source photography workflow application and raw developer. A virtual lighttable and darkroom for photographers. It manages your digital negatives in a database, lets you view them through a zoomable lighttable and enables you to develop raw images and enhance them.
Would be very nice cause it's a proper combination with Gimp!
Andreas
It is now in the poll and will be added soon to Patch My PC, make sure to vote for it
https://patchmypc.net/vote-for-new-apps