Newly free modular synth VST/AU for Mac/PC (Reaktor Player)
For those who may not have heard, Reaktor was just updated with front panel patching -- but even more intriguing, the free Reaktor Player now gives you a nice set of fundamental modular building blocks, for the first time allowing non-paying users to build/patch your own modular creations. -- Plus you can download something like a combined 80 free modules from both the Toyboxaudio pack and Unfiltered Audio's Euro Reactor 6.3 free expansion.
Both of those companies also offer a paid pack of modules, that'll also work in the free player.
I believe it's the first comprehensive virtual modular VST/AU that's completely free, though I may be wrong. (Not including VCV Rack, which isn't an actual vst plugin)