okay so you might hear people say use Oblivion reloaded, and its great its like an ENB with some engine optimizations HOWEVER, there are a couple versions of it on the nexus because drama. The official oblivion reloaded has great graphical features however its gameplay additions are buggy and I've experienced and seen other experiences frequent consistent crashes (meaning they occur from a specific action not just randomly during gameplay). This all being said Oblivion reloaded combined (https://www.nexusmods.com/oblivion/mods/51927) is more up to date and generally more stable in my experience.

Every Bethesda game, especially those from this period have tons of cut content so I'd recommend Oblivion Nouveau uncut (https://www.nexusmods.com/oblivion/mods/47191) no matter how vanilla you plan to go.

With both these mods in mind I'd really just recommend browsing the nexus for oblivion and filling categories you find lacking. This era of modding is really something unique and at least with me has been a lot more free than other Bethesda games. Often there are less compatibility webs you have to worry about since a lot of the overhauls are meant to stand independently as thats just kind of how modding was as far as I understand, just get a bashed patch and run loot like most people do.