Darktable is a quite good alternative for Lightroom. It's constantly developed, open source and free, does not require sign up, and it have number of modules for development of photos, beside a very good cataloguing, mapping and tagging options.
Beside other features it support:
You'll never find a real clone of LightRoom, but LightZone is an excellent free alternative.
Among many other features, it also supports...
Nondestructive RAW Editing
You can use Adroit Photo Forensics:
non-free but trial available
extract JPEG files from dump data files:
According to their Adroit Photo Forensics (from which you can see a few other applications if you want to give a try to them too):
PhotoRec is the only free (and open source) in the list.
Any RAW processing tool can do it
The most common ones on Windows are darktable and rawtherapee
Each camera manufacturer also have their own tools for editing their cameras' raw files, like Canon's Digital Photo Professional
Is there good free software for editing Canon RAW files?
How do popular free RAW editor/converter compare to each other on Windows?
Take a look at SILKYPIX, a RAW development product originally from Japan. The workflow is a bit different than the Adobe way of doing things, and it comes in three different levels.
SILKYPIX DS Pro series
SILKYPIX DS series
SILKYPIX JP series (only JPEG)
It is non subscription and there is a full featured 30 day trial, so you can see if it suits you are ...