Germany, Spain, Australia, Japan, Sweden?, Russia?, China?, India? France? That's off the top of my head. US builds only nuclear.
The submarine exporting nations are Germany, Russia and France.
Sweden tried it once but the Collins-class is still a financial disaster. Price is about twice as high as a European design and maintenance costs are exploding.
Spain tries to build the S-80. India is importing Russian submarines. Just Japan and China build indigenous submarines.