I was recently introduced to a digital service to help us to specifically pray for unreached people groups: Unreached of the Day by Joshua Project.
It gives you the option of downloading an app or signing up for emails.
It gives helpful prayer points, such as a summary of the people group (including country of origin), ministry obstacles, outreach ideas, scripture focus, scripture prayer, and statistics. We can click on their full profile, prayer cards, a bulletin insert, or a handout as well.
If we are Christians, we should be praying for the lost to come to faith in Christ. It is good to be personally praying for the non-Christians we know, but we should also be praying big prayers for entire groups all around the world to encounter Christ.