It's the best tool if you want to get rid of Adobe Lightroom, and you want to use something that is more powerful, free and fully customizable. With LUA plugins/scripts, you can expand the features to the level, where you have ease of use feature parity with some commercial RAW editors, and exceeds in other fields. The learning curve is steep at first, because the image processing pipeline is fully exposed to the user to tinker with, but that's one of the biggest issue for beginners, whom came from easy to use and understand software like Lightroom or Capture One, where the pipeline is fixed and you can only do certain steps in certain order, where as in darktable, you can edit and change that (to a certain degree). That is one of the most powerful feature of darktable, but this is the hardest as well.

The Affinity trio... No list of any Adobe competitor would be full without them. Affinity Photo is an amazing Photoshop alternative, and in many ways, it's even better. It's much more stable and the perceptual license means, you only have to pay once. You can still open and edit .psd files, but keep in mind, that the feature is quite limited, and you WILL run into situations, where Affinity can't open a file properly. It's not that big of a deal breaker, and it's own file format is actually amazing. You can edit the same project file on Mac, Windows and iPad even, so that means,

RawTherapee in my opinion is inferior to darktable, but certainly more user friendly. I would higly suggest to try it as well, because it's also free and open source

If you want a really powerful photo management program, this is it! I personally ain't using it anymore, because I only use darktable for photo database management as well, but it's a great standalone option to those, who misses Adobe Bridge

DaVinci is widely regarded ad the best tool for video color grading, so if for nothing else, use for that. But it's not just a really great color management tool, but rather a fully featured video editor. It's perceptual license model is great, and the free version is 99.99% of what someone would want from a video editor. The only locked features are rarely used (at least by me), and more focused towards bigger productions, rather than small creatives. It's much more stable than any other video editor, that I ever used, it's great for highly complex calculations as well, and it's has some industry leading hardware support in terms of both compatibility and hardware utilization

Have you ever been in a situation, where you had to convert a .mkv to a .mp4? This easy to use and weary powerful FOSS tool can do that and much much, more. Anyone, who does anything with a video footage, HAS to have this, because it can solve problems that would be incredibly difficult in any other software..

The best and universally loved audio recorder, editor and digital workstation solution. If you ever had to do anything audio related, you probably already used Audacity by some extend. Audacity is much much more than what 99.9% of the people use it for, so I would highly recommend, that you should learn the ins and outs of this handy program.

If you want to get into the world of 3D this should be your choice. Really capable, free and open, and you can do so many things with it. I used Blender for product feature videos, used for VFX, used it for TV commercials. You can't go wrong with as great as a tool as Blender. It's really hard to learn for the first time, and there is still a lot, that I should learn, but

Affinity Publisher is an amazing DTP software, with better and more stable performance than any other DTP that I ever used. The only thing that stands in between being this as my dream software when I work with printed materials, is the fact, that Scribus exists, and that's an excellent choice as well. But if you bought the Affinity V2 Universal license (as I did) I would still recommend over Scribus, just because of ease of use and the learning curve is not that steep.

I'm not that big of a vector or drawing guy, so this is where my expertise ends, I work with raster media, and some 3D and VFX here and there, but what I can tell you, that anyone, who started to use Affinity Designer instead of Adobe Illustrator, swears about how much more stable even with really complex vectors.

I'm not a digital drawing artist by any mean, but Krita is an actually amazing tool, and by far the best if you want to get deeper into the world of digital drawing and painting. It is a full fledged professional tool and if you are someone who has a Wacom tablet, you already know and love Krita.

If Affinity Publisher wouldn't exist, this would be my choice of DTP. But I still put this onto the list (unlike GIMP), because it's a solid alternative to InDesign.