Flox provides an extensive sql-like query language that allows you to find and sort players and entities. Check out some examples:
//retrieve all amplifiers that go to eleven
var query:Query = new Query(Amplifier, "goesTo == 11");
//retrieve all swords from the weapon rack
var query:Query = new Query(Weapon, "type == ?", "Sword");
//retrieve all of the player's friends by their ID
var query:Query = new Query(Player, "id IN ?", friendIds);