C139/C422 SCI controller working (for most linked Namco games).
Final Lap/Suzuka 8 hours games sound/graphics issues fixed (also applies to Four Trax)
Namco System 21 fixes.
Figure out why Alpine Surfer is unplayable in Mame. I personally think it's unemulated video or dsp functions since I can confirm it doesn't run on slightly different hardware.
Namco System 23 fixes.
Konami PPC 403GA family hardware (zr107, gticlub, nwk-tr and hornet) major fixes. I'm kind of in the process of acquiring a Thunder Hurricane pcb set to hopefully do a schematic of its I/O board. Also linked machines .
Racin' Force (Konami GX 1) playable. I can confirm it uses a K056230 for networking from looking at a pcb.
Polygonet hardware fixes. That game also uses a K056230.
Midway Zeus fixes. Also figure out the network controller. Is it some sort of SCI/shared ram controller like with the Sega and Namco games?
Taito JC timing issue fixed. I would mention its TMS320C51's internal rom but those are hard to find (and idk if that rom is specific to Taito JC). Network function as well (I need to add a dummy SMC COM20020 device).
Not to mention that device is used in Chase Bombers and Ground Effects. Gunbuster on the other hand is more of a direct link like the dual stack System 32 games.
I honestly got way too much to list to the point I'll stop here. Some may not get done in 2020 (obviously).