and many others; the rest; extras (in a film)
Used to refer to a large number of unnamed or unimportant people, often in contrast to a few named individuals. The film sense is a specific application.
受賞者は山田氏、その他大勢の候補者たちだった。
The award winner was Mr. Yamada, and the rest were the many other candidates.
その映画では、その他大勢とし
In that movie, hundreds of extras were used as the crowd.
A set phrase composed of その他 (sonota, 'the others') and 大勢 (ōzei, 'a large number of people').