Linda Audio has released the VST guitar amp simulator Rock Amp. No specific hardware simulated, no advanced circuit emulation algorithms used – just tuned to sound good to my ears. It is useful for rock and for low to mid-gain sounds, but it is also capable of something close to high gain.
This is only Amp simulator, it does not feature Cabinet simulator. For cabinet simulation you can use some free Impulse response VST plugin like Ignite Amps NadIR. There are 3 drive modes – CLEAN, ROCK and METAL which differs in gain amount but also in distortion character and pre-equalization used. BRIGHT switch engages algorithm which accentuates higher frequencies dynamically. It is very sensitive to the input signal level (this can be adjusted by INPUT).
PRE Equalizer not only shapes input signal frequencies but in ROCK and METAL drive modes also significantly affects the drive level and character.
POST Equalizer shapes output signal frequencies.
GATE features low pass filter on input signal controlled by envelope follower. Useful particularly for higher gain sounds, should be turned off for quiet lower gain sounds.
TIGHT affects how fast is the drive response to signal (the more tight – the faster drive amount falls).
FAT adds even harmonics to the signal.
BODY adds some middle and higher mid-range and some more aggression.
MOD is modulation effect which can be set up like chorus, flanger or vibrato. In mode I there is one delay line, in mode II there are two delay lines creating richer chorus effect.
DELAY is simple delay effect with overdrive and filter in feedback loop – it can be introduced by THRESH amount