Cores supporting RTC

If you have internet connection or RTC board installed, these cores will show correct time and date and/or be utilised by the core.

ao486 (PC) (DATE on MS-DOS prompt)
Archie (Acorn Archimedes) (Apps > Alarm)
GBA (checked with Pokémon Sapphire, wall clock in first room)
Gameboy (GB and GBC) (Pokémon Gold: set clock, go one room right, set day of week, save, restart; clock is in the menu screen)
MSX ("MSX3") (DATE on MSX-DOS prompt)
BBCMicro (BBC Micro Master 128K) (PRINT TIME$ in BBC Master mode)
Menu (on top of the panels)
Minimig (Amiga) (Utilities > Clock)
NeoGeo ([DIP] Settings: ON > BOOK KEEPING > CABINET/COIN, check date of log entries)
PC8801mk2SR (PC-88) (PRINT DATE$, shows year 85 but month and day are OK, and PRINT TIME$ shows correct time)
Pokemon Mini (Time & Date on in game menu)
QL (Sinclair QL) (PRINT DATE$)
SNES (Daikaijuu Monogatari II, Tengai Makyou Zero - once set up, you need to reload the core for the clock to take the real time)
TSConf (top of Wild Commander screen, also MaxiClock plugin)
X68000 (DATE on HUMAN68K prompt)
Zet98 (PC-98) (DATE on MS-DOS prompt)
ZXNext (ZX Spectrum Next) (main menu in Next mode)