100% agree. Milkdrop visualisations were awesome. There are some replacements available (you can check out Plane 9), however, I find them nowhere close to good old Milkdrop.
Or maybe it's just nostalgia?
Or maybe it's just nostalgia?
- https://github.com/projectM-visualizer/projectM
There's even pulseaudio/JACK versions of projectM that allow you to pipe any audio source into projectM to visualize. Enjoy!