Off the top of my head, stadiums I've been to games in the FBS:

Wake Forest (vs. BC, vs. Utah State)
Duke (vs. UVA, vs. Baylor)
Appalachian State (vs. Liberty)
Clemson (vs. BC)
Georgia Tech (vs. UVA)
Georgia State??? (I guess if you count going to a Braves game? Otherwise, no.)
Florida State (too many times to count, my alma mater and hometown team)
FAU (for 4 Florida vs. the nation high school games, never for an FAU game)
FIU (vs. Louisiana Tech)
Miami (vs. FSU)
Troy (vs. Texas State, vs. Navy, and 1-2 other games I can't recall at this time)
Oklahoma State (vs. Texas)
BYU (vs. FSU)

Bowl Games / Neutral Site Games:
FSU vs. Colorado (Jacksonville)
Notre Dame vs. Navy (Jacksonville)
ACC Championship Game: FSU vs. GT (Charlotte)
Gator Bowl: FSU vs. WVU
Gator Bowl: UVA vs. Texas Tech
Champs Sports Bowl: Maryland vs. Purdue
Champs Sports Bowl: Boston College vs. Michigan State
Orange Bowl: Louisville vs. Wake Forest
Peach Bowl: FSU vs. South Carolina

FCS:
Samford (vs. App State when FCS, vs. Murray State)

D2:
Valdosta State (about once a year for the past 10yrs, plus several high school games)
West Florida? (Only if you count a minor league baseball game.)

Never been to a D3 or NAIA game.

I've also walked inside many, many, many more stadiums and taken pictures but never been to a game. Too many to list. Everywhere from SMU to TCU to Southern Miss to New Mexico to Weber State to Vanderbilt; on and on.

**************
Places I'd love to see a game:
The rest of the ACC stadiums I haven't been to yet.
Army
Michigan
Ohio State
Alabama
Auburn
Texas
Oklahoma
Georgia State
Georgia Southern
Liberty
Tulane
UNC Charlotte
UCLA
USC
Hawaii
Jacksonville State
Montana
North Dakota State
JMU
Grand Valley State
Plus several others I can't think of off the top of my head.

****
Some random notes from my experiences:
- My experience at Clemson was awesome. Probably my favorite place I've been to so far. When I went I had a very negative view of Clemson fans, after my time there I totally changed my opinion and now I respect them quite a bit. I had a wonderful time, everyone was very friendly, and it was a great game-day experience.

- Similarly had a very good time at GT. Not quite the atmosphere as Clemson, but I actually really, really liked the view from Bobby Dodd Stadium. You feel like you're literally on the field, it's so compact. Plus the view of the Atlanta skyline all around is very neat. Combine that with the Varsity within walking distance and the GT hall of fame which is open for visitors, it's a fun experience.

- App State and BYU are by far the most scenic venues I've been to. BYU is probably unrivaled by any FBS school in the country. What an amazing view. People there were very nice as well, although the crowd was a little subdued. App State's Kidd Brewer Stadium is really a great place to see a game, nestled in the Appalachian mountains. I got to watch the game there in a box which was neat.

- Duke's Wallace Wade changed a lot between the two times I went. It's a historic stadium. Home to the only Rose Bowl game outside the Rose Bowl. It looks even nicer with the addition of all the boxes, but it does feel just a little less "classic" to me now.

- Wake Forest was fun both times I went. Nothing really much to say other than I think it's where my wife and I went to our first college football game together.

- Troy is one of my selfish favorites. They play some interesting teams at home and tickets are cheap. It's a really nice venue and the crowds are pretty good. I really like Troy's band and I always enjoy going there.

- FIU was awesome because I could spread out so much. It was homecoming and there was practically no one at the game. About 1,000, maybe less by halftime of a competitive game. I don't say that out of hate, hopefully it's gotten better. My mother was in the second graduating class there and my mother-in-law works for the dean. It's a small place, but close to the field and all the seats are comfortable.

- I have a biased view of Miami because my experience there wasn't the typical one. My grandfather-in-law is an Iron Arrow with them and has a box, so when he took me to the FSU-UM game back in 2014 I got to get my picture with Sebastian at the booster tailgate and watch the game from his box. It was an awesome time and one of the best games of the series in recent years.

- Oklahoma State was a lot of fun, although I wish there were a few more pregame traditions. I'm really into experiencing a school's traditions and really enjoying it all, and I felt like there wasn't a whole lot. At least not that I could readily find out about in my own research.