Please post “Working” VST's in Jammr and the description of what they do here.

ReFX Nexus - Synthesizer
DrumBurst - Drum looper
Pod Farm2 - Guitar Amp & effects

GuitarRig 5 - Guitar Amp & Effects

LesLiKe
Please post “Working” VST's in Jammr and the description of what they do here.

http://www.kvraudio.com/forum/viewtopic.php?t=268277
ZynAddSubFX VST version (free)

Transform your laptop in a 2 octave keyboard synthesizer with nice sound bank (no other instrument required) for portable jamming.

Guitar Rig4 of course also…
S-gear
Vandal
mp3play2 - play mp3 as backing tracks
Mobius - Looper software (hard to drive)
deckadance - maybe interesting for hiphop and similar

AmpliTube 3
http://www.ikmultimedia.com/products/amplitube/
both free and paid software (It was an epic to install but I gave a try)
Thanks Hans for suggestion!

http://www.native-instruments.com/en/products/komplete/guitar/guitar-rig-5-player/

Free Lite Version

Heres some more working VSTs
Cakewalk Studio-Instruments

daHornet

I use Pod Farm 2 for guitar effects.

addictive drums 2 work fine