Are there any mods that add just blank land away from the main Morrowind island?

huh? :shrug:

Do you mean a mod that'll add a random landscape with nothing on it? That'll take you 5 minutes in the CS.

Do you mean a landmass mod with towns and quests and stuff? You should try Tamriel Rebuilt and Silgrad Tower then.

Project Tamriel as it is at the minute :facepalm:

Yeah I know it wouldn't take long in the CS but the blank/endless sea is really creepy to me, don't ask why, I don't know xD it's just weird.

Have you heard of Abot's "Water Life" mod? It can be found here:
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=258

It adds lots of new underwater content for Morrowind.

For example, in the deep sea "wilderness", you can randomly find undersea palaces, lost shipwrecks, and treasure.
It also fills the seas with new creatures, like whales, sharks, and many kinds of fish.

The new creatures don't only spawn in the deep sea.
You can find the smaller fish in any body of water, like in underwater caves, for example.
You can even go fishing with a fishing rod!
(and as an added bonus, it can be set to make slaughterfish passive, so they don't pester you as much.)

It's one of my favorite mods, I use it all the time.
Hopefully, this should spice up the deep sea areas for you.

If you really want a blank land with almost nothing on it, there is the http://www.tesnexus.com/downloads/file.php?id=7339 mod.