Scads means a very large number or amount of something: scads of money, scads of people, scads of old photos. It is informal American English — friendly, and to many ears a little old-fashioned or folksy. You might write it in a chatty story; you would not put it in a school essay or a news report. British speakers are more likely to say loads or tons. Nobody uses it to count one by one; it only means “lots.” It almost always appears as scads of, not as a single scad.

一大堆、超多（美式口語）