Atik legacy and modern (Mac support is spotty still as there are issues in Atik's Mac library)
Canon DIGIC II* / III / 4 / 5 EOS DSLRs.
Fishcamp Starfish
Meade DSI, DSI Pro, DSI II, DSI II Pro, DSI III and DSI III Pro.
QHY 8, 8L, 8Pro, 9, 10, 12
QSI 500 / 600 series
SBIG
Starlight Xpress USB2 models (SXV / SXVF / SXV-R / Lodestar / etc. including those converted to USB 2 via the SX adapter)
ZWO ASI

In addition, on Windows, the following cameras are supported
ASCOM-5/6 compliant cameras
Apogee cameras
CCD Labs Q8-HR / Q453, Q285M / QHY2 Pro
FLI cameras
Moriavian G2/G3 (v3 or higher firmware)
Orion StarShoot Deep-Space Color Imager (original) **
OpticStar DS-335 series, DS-336C, DS-615, DS616, DS-142, DS-145, and PL-130
SAC10
SAC7 / SC1 long-exposure modified webcams / Atik 1 and Atik 2 cameras.

* Earlier DIGIC I Canons (e.g. the 300D) are not supported. Also, for the DIGIC II cameras and even some DIGIC III cameras, Canon has declared them "unsupported" by their Software Development Kit. Most do continue to work, but it is not clear if this will change in the future and this does interact significantly with the OS you're using (e.g., many if not all DIGIC II's are not supported for capture on Windows 7/8 and others have issues in OS X 10.8.5 and higher). This is not something I can control and if you're considering purchasing, please download the fully functional demo to ensure things work on your setup prior to purchasing.
** The Orion StarShoot II, Pro, and other current "deep space" ones are not supported directly but are supported via their ASCOM drivers. Their "Solar system" cameras can work (as they are similar to webcams), but keep in mind Nebulosity is designed for deep-space photography.

Nebulosity Release Notes: 4.4.4

4.4.4 (1/18/21)
- Updated to LibRaw 0.20.2 for CR3 support
- Use LibRAW preference applies at capture as well as loading for better Canon support