Oblivion

[Extreme Angle]

I'd completed all of the main questlines, And explored most of the map,
Name some of the hidden stuff you found when you were exploring, here's mine.
The invisible troll up by dive rock, read the diary entry up on dive rock then go east and you will see the body of the person who wrote the diary entry, then you get attacked by an invisible troll.
The troll who ended it all - there's a troll under a bridge somewhere, he has a suicide note on him when you search him.
The fin helmet of gleam - bottom left of the map under water is a green glass helmet which gives night eye and something else....
There's also a giant mud crab, never found that.