Hybrid Graphics refer to systems with an integrated video card (for less performance and lower power usage) and a discrete video card (for better performance but a higher power usage).
Known combinations for integrated and discrete are:
- Laptops with Intel + nvidia (GT xxxM) are often using nvidia-optimus technology. See also How well do laptops with Nvidia Optimus work?
- Laptops with Intel + AMD
- Laptops with AMD + AMD
- Some HP all-in-one desktops have Intel + nvidia. It's called Synergy?
These hybrid graphics setups are still not well supported as of Ubuntu Precise 12.04. The blog http://linux-hybrid-graphics.blogspot.com/ and the related Launchpad group are useful resources. The Ubuntu Community Help Wiki is an good resource too.