The Din of Battle Blog has a nice scenario for a Boxer Rebellion Battle of Yangtsun, as well as an after-action report.
Here’s a photo video collage of a Boxer Rebellion game I ran a couple of years ago. The figures are all Old Glory. All figures and terrain were painted/made by yours truly.
Sand Pebbles Boxer Rebellion Edition is a set of free wargames rules from Bill Molyneaux.