Not just a modern application with a retro gaming aesthetic, but this year I got heavily into using (ex-Autodesk, now open source) Animator as my programmer art application of choice. Actual 16-bit software.

https://github.com/AnimatorPro/

https://github.com/AnimatorPro/Animator-Pro/tree/f5ed37135ad...

Fun restrictions to work with/around and it has some fun features too. Running in DOS also makes it run everywhere, including on my phone.

Would be happy to use more old DOS software, but I just have not found more that seemed as useful (maybe VGAPaint 386 for a different paint app?). No constant (forced) upgrades to keep up with. I can compromise a lot with features if it means that I can spend years/decades on mastering a tool instead of just barely keeping up with how the latest version works. (Guess that is why I always liked Emacs so much.)