Propellerhead introduced a new Rack Extension synth inspired by West Coast (Buchla) synthesizers - Complex-1
Complex-1 offers freely patchable environment with pre-built modules.
You can't change modules but you can easily rewire your patch without switching to the back of the rack.
Modules list of Complex-1 is very comprehensive:
Complex OSC with FM and AM, one extra OSC (variable saw to triangle) and 3 variable Waveforms, Random source, Noise OSC, Waveshaper, CombDelay, LFO, Filter, Two Low Pass Gates integrated with AD envelope and envelope follower, Math functions, ADSR, Mixer, Quantizer, Sequences, Two clock generators and more.
Sound is pretty good (synth uses 4x oversampling) though Softube Modular sounds much closer to the actual hardware (particularly Softube's Buchla Complex OSC and Doepfer's LPG).