Tactile Sounds TS-Substance
Platform/format: PC/VST Download
If you were asked to come up with a list of things that you'd like to see in a new free soft synth, simplicity, flexibility and (good) sound quality would probably be on it. This is what Substance promises: it was inspired by the classic analogue polysynths of the past and has two oscillator sections, two LFOs, two envelopes and two filters.
AuraPlug Freetortion Series
Platform/format: PC, Mac/VST, AU Download
OK, it's not new, but Mac users should be aware that Auraplug's Freetortion Series, which contains six guitarist-friendly amp/FX plug-ins, has just been ported to OS X. The only stipulation is that you'll need an Intel-based machine to run them.