UPDATE 2022/12/03: Check out Reveal Map Markers Extended at Oblivion Nexus - mods and community (nexusmods.com) for a more feature-complete spin on this that should work better with Shivering Isles in particular!

I'm currently playing through Oblivion, and have finished exploring Cyrodiil -- but have I?

I wanted to find out if I had actually found all map markers that can be encountered via exploration, but there was no good way to do this that would let me differentiate between places I've already visited and places I still need to visit.

I found an old mod that tries to do this, but it depends on a hard-coded list of locations, plus edits to map markers that conflict with Unofficial Oblivion Patch.

Reveal Map Markers (RMM) is much more flexible: It uses OBSE functions to scan *all* map markers and enable (mark as known but not visited) any that are not yet known. This means that it should support mods that add locations while not conflicting with any other mods.

Notes:

• RMM ideally runs just once whenever you start a new game or load a saved game.

• Sometimes OBSE returns an empty set of map markers, so RMM will try up to 100 times to get the list. You will get an on-screen message with the final result, and in any case it seems to work if you reload your saved game.

• RMM intentionally ignores Oblivion gates and Map Marker Overhaul player markers, because it doesn't make sense to activate them even though doing so seems to accomplish nothing.

• A few locations seem to get activated but are still not visible on the map, such as Kvatch and player housing markers added by mods; this is likely for the same reason as Oblivion gates an MMO player markers - they're probably located off-map and then moved into position when activated by quests/mods.

• RMM seems to have no effect on Shivering Isles locations.

If you just want to check for missed map markers without permanently activating them, you can do the following: activate RMM, load your saved game, view the map, then quit the game without saving and remove RMM from your load order.

This mod only requires OBSE and no other mods or content beyond the base game. It has been checked with TES4Edit to ensure there are no dirty edits or extra depedencies; it only adds a quest and a script.

I do recommend using this with Map Marker Overhaul, because MMO makes it easy to turn off visited locations so that you can focus on just the known ones.