From the release notes over at atari-forum and here, I've found the following cores are mentioned as supporting ADC.
- Spectrum (tested myself)
- Amstrad
- Apple II
- ADCTest
- (Unofficial) MSX1
- Acorn Electron
- Lynx 48 and 96
- Oric
- CoCo2
- AliceMC10
Similarly, I have not found a list of cores that support the RTC, and from the release notes I have found these:
- Linux
- Menu
- Minimig
- QL
- Archie
- NeoGeo
- SNES?
- GBA?
- ao486
- X68000
- PC8801
- MSX