I don't want to sound like a dick and say all of them but yeah, pretty much all of them... I strongly recommend you find a 'Best of AJ Styles: The Phenomenal One' on DVD on eBay or somewhere. Totally worth it.
Notable matches in my opinion are;
Styles vs Daniels vs Joe (Unbreakable 2005)
AJ Styles vs Abyss (Lockdown 2005)
Styles & Daniels v LAX in Ultimate X.
Styles vs Joe (Turning Point 05, I think)
And there's so many more I could name; the list would go on for too long.