Sports, art, and... murder one.
http://www.nintendoworldreport.com/news/50654/june-update-for-switch-online-nes-library-revealed
The June lineup of NES games for Switch Online will hit the road, a ball, and a lot of thugs.
June's additions, due on the 12th, will be Volleyball (Nintendo), City Connection (Jaleco), and Double Dragon II: The Revenge (Technos/Arc System Works). Both Double Dragon II and City Connection have releases as part of the Arcade Archives.
There are a total of 716 known licensed game titles of which 678 were released in North America along with 2 championship games. 35 were exclusively released outside North America