When reading Chronicles of Nchuleft and The ruins of Kemel-Ze, there are certain dwemer ruins mentioned on the mainland that are not in TR yet. The ruins are:
Leftunch apparently is where a "Lord Lhlendam" is buried.
Hendor-Stardumz is in a place that the dwemer called "Chinzinch Pass" where there were creatures that killed Lhlendam.
Bamz-Armschend was a dwemer Council Hall of some sort.
Raled-Makei is plundered and probably has lots of scholars in there, as in it's a popular ruin to go to and would be deemed a safe one for the general public to visit and see the dwemer architecture up close.
Would these ruins be in TR? They're all mentioned in the lore. I wouldn't mind making them if people don't want to make them. I seem to think that they would be in the Telvanni and Indoril Lands. Aside from Raled-Makei. That would probably be in close proximity to Cyrodiil so Hlaalu lands most likely.