ICC Help: best
Shows the top 22 active players in terms of ratings for one or more rating categories. An active player is an established one (has played at least 20 rated games) A player's blitz rating is active if that player has played 8 rated blitz games in the last 31 days. The requirement is also 8 games for bullet ratings to be active. For standard and wild games, the requirement is 6 games per month. For 5-minute and 1-minute, it's 8 games in one week. For 15-minute it's 4 games in one week. For correspondence, 2 games in one year.
Words the "best" command understands are: computers, blitz, standard, bullet, 15-minute, 5-minute, 1-minute, wild, loser's, crazyhouse, bughouse, correspondence. You can use any combination of those, and abbreviate them. E.g. "best wil los craz bug" to get a four-column output of best ratings for chess variants.
Players with more than one account are included only once on the best list. Free-trial accounts are not listed.