In order to get on the rating leaderboard you must:

1. have played at least 30 rated games in a given rating,
2. have played a rated game within the last week for this rating,
3. have a rating deviation lower than 75, in standard chess, and lower than 65 in variants,
4. be in the top 10 in this rating.

The 2nd requirement is so that players who no longer use their accounts stop populating leaderboards.