callbacks.has()

Determine whether or not the list has any callbacks attached. If a callback is provided as an argument, determine whether it is in a list.

jQuery.grep()

Finds the elements of an array which satisfy a filter function. The original array is not affected.

jQuery.uniqueSort()

Sorts an array of DOM elements, in place, with the duplicates removed. Note that this only works on arrays of DOM elements, not strings or numbers.