One of my favorite combos is Clio Cup at Oregon Raceway Park. I use 50% aggression and set the difficulty so I can hang with the leaders, but not necessarily win. Typically run a practice session and compare lap times, then in & out while I adjust AI difficulty. Always make the AI qualify, but sometimes I qualify and sometimes I just start at the back.
For the ISI-only material, I started keeping records in Nov 2015 since I was offline. Now that I'm back online, at least sometimes, I haven't been so intent on keeping the records. You can see where I got to...
https://docs.google.com/spreadsheets/d/1ih5ONsr4EAR309yPncvqy9XGy5-T4Od41ntH66hH5KA/edit?usp=sharing
I enjoyed the Apex GT3 for a bit, trying to get decent setups, then got back online with historic F3s (F3 Fanatics and F3 Rookies) and BT20 (TGP has an open series that I'm late entering).