I've been finding some good stuff here:
https://pixls.us/Bit by bit I'm getting rid of a lot of proprietary stuff. Libre Office instead of MS Office.
Pixls.us has a nice list of software here:
https://pixls.us/software/GIMP has replaced Photoshop.
Digikam I discovered as a potential Lightroom replacement. Looked great, but unfortunately it crashed constantly for me, so I ended up getting three licenses of ACDSee Ultimate for fairly cheap.
Others I've used in various ways that they list
Imagimagick - I've only used it on the command line on Linux, but very solid
Lots of other stuff that I haven't tried that look like viable replacements for some of the more expensive software out there.
