JPEGView It's a simple but powerful image viewer (don't be misled by the name, it can view most any standard image formats).
It feels weird to even have an opinion on such a simple piece of software, but this is the type of tool that reminds you of what software could be like. When you open an image, you see the image. No loading time. No unnecessary toolbars. No fucking pop-ups to update the software to get the latest AI tools.
Don't get me wrong, it's plenty powerful. It's got all the tools you'd expect: viewing EXIF data, cropping, rotating, brightness/color correction. It even has some more advanced tools: navigating collections of photos (including nested folders), viewing a collection as a slideshow or movie, perspective correction, batch-renaming... The impressive part is that it does all this without getting in the way of it's job: viewing images.
Unfortunately, the project has been abandoned, though it appears to have been forked here (I haven't actually used this version, but hopefully they haven't changed too much).
Is there a particular draw for foobar2000? I remember a while back I was looking for a music player and that kept coming up, but I found it underwhelming when trying it. I've been using MusicBee for a long while now, and have found it excellent, so I don't plan on switching, just curious if there's something I'm missing.