Every driver you could possibly need for any hardware in the last 20 years? This is a live CD and is expected to just work no matter what you’re running it on.
Edit: Also, of course, every program you might need to usefully test-drive a distro, like office apps, media players, image viewers, browser, email client, and a myriad more. Now that I’ve said it I find 6GB remarkably small.
Fedora also by default includes only free stuff. AFAIK Ubuntu includes non free codecs for media and other software that doesn't fit in FOSS category (it's also one of t
the reasons why Ububtu became so popular in my opinion, it just works works out of the box)