Modular synths are a rabbit hole one descends into like a frog boiling in water. Slowly adding modules and patching modulators into sound sources. It can be quite fascinating as the complexity increases exponentially. Some good places to start in the popular Eurorack format are:
Forum: https://modwiggler.com/
Manufacturers:
https://www.makenoisemusic.com/
https://pichenettes.github.io/mutable-instruments-documentat...