I was wondering if you guys could help me find good mods that add other lore-friendly provinces to Tamriel? I know about Elsweyr, of course, and have downloaded that one already. Any others that you would recommend? They don't have to be 100 % complete, but they should be playable, preferrably with several settlements, unique landscapes/exterior designs, NPCs and quests.

I am going through Nexus myself, but it's good to hear feedback and experience from other gamers on what worked and what didn't. Any recommendations are appreciated.

http://oblivion.nexusmods.com/mods/40005 : a project to make all the countries in the same world map as Cyrodiil. Elsweyr is part of this project as well. It has a ton of links for all it's project parts. This page for http://obge.paradice-insight.us/wiki/LLOD_(Module) also has a list of the TWMP mods (this one's a bit easier to read).
Just be aware that to get them all means you'll have around 40 esps+bsas in your data folder and they total several gigabytes to download it all....