Venom VB-303

Venom VB-303, a brilliant free Roland TB-303 emulation
http://www.kvraudio.com/forum/viewtopic.php?t=380007

Beat Subtraxx

Beat Magazine has announced the release of Beat Subtraxx, a freeware trance synthesizer in VSTi plugin format for Windows.

Four powerful VA oscillators, envelopes, LFOs and filters galore, this trance-gate, arpeggiator and a more than full FX section – these are the impressive Main features of our “Beat Subtraxx”.

http://www.studiodrive.de/?t=plugins_overview

Xen-Harmonics FMTS

Xenharmonic FMTS is a 4 Operator FM Synthesis VSTi with a specialized set of features for musicians interested in exploring the expressive possibilities of microtonal and xenharmonic music making.