Darktable - darktable is an open source photography workflow application and raw developer.
Halide - A premium camera for your phone
RawTherapee - RawTherapee is a free RAW converter and digital photo processing software.
NightCap Camera - NightCap Camera is an exceptional tool that is used significantly in low light and night time to make dark photos looks like they were made in full light, developed in the market by Realtime Dreams Limited Inc.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Camera+ - With Camera+ you’re able to use your iPhone to shoot the best photos you possibly can.