Papaya is a free physically modelled mallet VST instrument synthesizer. Papaya features a nice chorus module, and does a very good job of simulating steel drums, and other carribean type percussion.
Minerva is a free granular VST instrument generator for greating percussive sounds. there are 80 source wavelets for each channel, 40 short and 40 long. all short wave sources are velocity sensitive and all sources are pitch shiftable. each channel has a separate granular processor with pitch, size and rate paramters as well as random adjustors. finally a nice bitcrush rounds each channel off. white keys C-3 thru A-3 are the triggers.
Field is a free multisample based ambience generator vsti plugin. using original field recordings by twerk, field allows you to generate suitable backing ambience for any track.