Subs Completed:
1)Project 673

2)Skipjack Class SSN

Subs in progress:
1)Whiskey class submarine (Long Bin SSG variant)

Subs to build:

Cold War west German U-Boat type 206 Diesel Electric Attack Sub.

Soviet Sierra Class Nuclear Attack submarine.

Russian Yasen Class Nuclear Attack Submarine.

British Churchill Class Nuclear Attack Submarine.

The Scinfaxi Submarine Aircraft Carrier/SSBN from Ace Combat.

Having set the precedent here, I will prioritize accepted sub requests over subs for this list. That in mind, feel free to post any submarine requests here and in any future updates. I may tell you if I've accepted, OR I might not and let it be a surprise ;).