https://www.youtube.com/watch?v=5rcRcokDlqI
In this video I check out the SOCAL Labs 8-bit Treat VST plug-ins released by Tracktion developers. These plug-ins are available in 32 and 64 bit and as AU, VST, and Linux VST.
I play demos on some famous video game MIDI files and then examine each plugin in depth.
Quite quirky but definitely some good stuff here, esp. for chip junkies 
Check out the plug-ins here:
https://www.tracktion.com/products/8bit-treats
(You have to give them your email and stuff to get them)
Papu:
Emulates hardware of Nintendo Gameboy.
2 Square wave channels.
Sweeps on first square wave channel.
1 Noise channel.
RP2A03:
Emulates Ricoh 2A03 of the NTSC Nintendo Entertainment System.
2 Square wave channels.
1 Triangle wave channel.
1 Noise channel.
SID:
Emulates MOS Technology SID of the Commodore 64.
3 Oscillators.
4 wave shapes: Square, Triangle, Saw, Noise.
ADSR per oscillator.
Ring modulation (replaces triangle output) and hard sync between oscillators.
HP, BP, LP filters.
SN76489:
Emulates Texas Instruments SN76489 of the Sega Master System and other consoles.
3 Square wave channels.
3 Note polyphony.
1 Noise channel with 2 types.