related concepts are the "adopt a people" programs that show the needs of different ethnic groups and also consultations on world evangelization by which different church bodies make plans to target certain "unengaged" people groups.
At:
People Groups: Downloads you can see the spreadsheet of the best-ascertained list of "unengaged people groups" that lack the Bible, churches or resources or vehicles to spread the Gospel.
The ACCESS List - The ACCESS List of Unengaged People Groups of Central Asia Finishing the Task - About
Right now, acording to the best available agreed upon definitions (which are not perfect), there are 3,323 unreached people groups in the world who are not currently engaged by evangelical Christians. Of these, 636 have populations exceeding 100,000 each. Again, it is my thesis that these 636 groups ought to be prioritized and prayed for specially.