I think I posted about Sideways Cave before and how it's a good place to come when you're a wee little adventurer? I think I also mentioned that in the "Lost Abagarlas" zone that there are a set of 3-4 iron gates that keep you away from the last area which contains (3) gargoyles and (1) mystical imp?

Well, I went back there at level 8, with a bit more power under my belt. Poisons that do 4 points of damage per second for 15 seconds, steel arrows, better marksmanship skills, etc.

Apparently, I haven't found what they're weak to, because the poison barely moves their health bar. Plus, when a gargoyle gets damaged, they shield themselves (becoming stone) fall over and regenerate. I'll come back after preparing a fire / cold poison and after getting a few more levels.

(Tested with Oscuro's Oblivion Overhaul 1.33. Rumors indicate that they may be roughly level 20. I dragged an outdoor gargoyle through a pair of guards on the road outside of Skingrad and the gargoyle wiped them out. Hopefully it will despawn before I have to travel back through there.)

...

The other low-level dungeon near the Imperial City is Vilverin. It is guarded by a trio of bandits outside and a bunch of bandits in the first section. After that it switches over to skeletons and other undead.

Once again, the first 2-3 areas are doable at levels below 10 (I did well at level 8). But the final area contains a boss and spectral warriors / wolves that will give you trouble without the proper equipment. I figure I'll come back at around 12-15 when I have weapons that are enchanted with shock.