http://online-go.com - go server

http://81dojo.com - shogi server

http://en.lichess.org - chess server

http://eidogo.com, http://josekipedia.com - go joseki/fuseki encyclopedias

http://chesscademy.com - chess training website

Youtube might not count as a small website, but I like these channels:

- https://www.youtube.com/user/onbaduktv - go videos

- https://www.youtube.com/user/hidetchi - shogi videos

- https://www.youtube.com/user/powerplaychess - chess videos