Sonic Pi is SuperCollider, but using Ruby instead of the default sclang language. Overtone is similar (and possibly originally by the same developer, iirc?) but using Clojure, and is also missing from the list.

Yeah, that's some glaring omissions - not including Sam Aaron's work makes me distrust the whole list. SonicPi is fundamental for teaching kids music and programming and Overtone is just mind-blowing - I watched people DJing music while evaling things in Emacs, that looked sick.