Joshua Project
The Joshua Project is attempting to “bring definition to the unfinished task” by cataloging information on all of the people groups of the world. Think of it as an evangelistic encyclopedia for humanity.
Currently, they’ve identified the different groups in each country and are steadily working on filling in details. It’s a great way to learn about how to pray for a country; however, if this is something that strikes your fancy, you might consider researching a people group help them out. This listing about the Manchu people in China is a great example of the kind of information they’d like to have for every people group on the planet.