jQuery & jQuery UI Documentation

Filtering

.eq()

Reduce the set of matched elements to the one at the specified index.
.filter()

Reduce the set of matched elements to those that match the selector or pass the function's test.
.first()

Reduce the set of matched elements to the first in the set.
.has()

Reduce the set of matched elements to those that have a descendant that matches the selector or DOM element.
.is()

Check the current matched set of elements against a selector, element, or jQuery object and return true if at least one of these elements matches the given arguments.
.last()

Reduce the set of matched elements to the final one in the set.
.map()

Pass each element in the current matched set through a function, producing a new jQuery object containing the return values.
.not()
Miscellaneous Traversing
Remove elements from the set of matched elements.
.slice()

Reduce the set of matched elements to a subset specified by a range of indices.