PC Engine = Magic Engine/Ootake
MSX = MeiSei
Game Boy series = VBA-M
Intellivision = jzIntv
PSX = pSX
Just a few additions to your great list, Retro-Nerd. MeiSei is a nice little MSX1 only emulator, not so bloated as the other MSX emulators out there. Also VBA-M, which is a fork of the original, and still highly maintained. pSX is an all-in-one straight forward emulator, just click and go. Of course you can use MESS for INTV and the MSX systems.
I forgot, Nestopia "undead version" is continuing to be developed.