Yes, foot toys are toy parts strung on small lengths of bird safe rope or leather and tied that they hold and turn in their foot and chew. Breezy loves them.
I'm not really ahead of you on this one. From seeing them at bird fairs etc., my assumption is that they are called foot toys because they are things the bird can hold in with one "foot" while they chew. Maybe someone who really knows will come along and set us straight!