I guess the problem is having it repeatable.
Also, the ENB makes it easier to take benches.
Skyrim with a lot of mods would be nice to have datapoints on but then we'd probably have to get any participants to download a 100GB+ Wabbajack modlist.
There are two current Oblivon Wabbajack modlists too.
What might be doable is a Fallout 4 GotY save game with a large user settlement and automations to stress NPCs and drawcall more than DiamondCity does.
If you want to decrease FPS, you can set weather to raining. That drops FPS a bit and I do it for all of my personal testing. I have a FO4 save where I get 13 FPS lol. Maybe I am a pessimist, but I expect it to be hard enough to get anybody to test vanilla Oblivion, let alone download a bunch of mods. I could try to find saves with more stable FPS. I have a personal test with my mods that is more consistent, but of course it just uses my own load order.
For Oblivion, I think just having ImpeREAL City mods will tank performance enough on its own.

I'm a bit confused how JZ scored 36% higher FPS vs ZiiZoraka's 5800x3d. They even have similar ram, both being 32GB cl14 with only a small difference in 3800 vs 3600. Ditching the result with AMD GPU for a second, JZ still has 22% higher FPS than fish's result. So where I'm at is:
1. I don't understand the 22-36% performance disparity
2. The results are for FO4, and Oblivion is pretty far removed from FO4's engine.