I've been reading some Flash stories and enjoy Jay's presence. What are some other stories before the reboot that are about Jay? Where is the best place to start. Ideally, I'd like to stick with the 1990s onward.

You can start with Flash Comics #1 from 1940. No, sorry, I know very little about Jay Garrick, I just had to get that out of my system.

Bump. I know there's two books compiling a lot of Jay's actual golden age comics, but they're quite difficult to find as physical copies and haven't been put on Comixology. I'd like to know where to start with pre-N52, pre-crisis Jay, but it seems next to impossible.

I got to know the character by reading JSA books. I don't think he has had any solo books (minis, one-shots, ect) since the Golden Age. So reading JSA is your best bet to see him.