Everything you can play on a chessboard[1]; you can buy cheap, lightweight plastic/rubber travel boards all around the world for about $1. Or you use a sheet of paper, draw your own board and play with crown corks. Or in sand with coconuts.

And you'll find people to play with even when you don't speak a common language; I have very fond memories of playing all of the staff of a bar in Copacabana, Bolivia, until sunrise (just knowing the little Spanish(es) I had picked up in the 6 months before) :)

Also, Dominoes, though a good set is rather on the heavy side.

[1] https://en.wikipedia.org/wiki/Checkerboard#Games_and_puzzles...