Part of the appeal of excavators is the litany of attachments, each of which allow the machine to perform different tasks. You can find dozens of types of attachments, but there are a few that are pretty commonplace:

Buckets - the stereotypical attachment on an excavator. They scoop up earth or debris with ease, partially because of the teeth lining the edge. Buckets come in just as wide of a variety as excavators themselves - you can find many different sizes!
Couplers - an essential excavator attachment, this lets you quickly detach and reattach other attachments. Without a coupler, it takes significant time and energy to switch out pieces.
Clamps - attach alongside a bucket to help assist in larger or heavier loads. The two pieces grip onto obstacles like boulders and tree stumps for an easier removal.
Augers - useful for drilling especially, these attachments include a blade and hydraulics to power it. These come in many specificities, depending on the size of the hole and what you’re drilling into.
Breakers - essentially a giant jackhammer, excavators can use this attachment to break apart hard terrain and materials – as the name would suggest.