Whiplash, Palm Springs, and last year's CODA all got their start at Sundance. Typically in March, South by Southwest (SXSW or "South By" if you're cool) arrives, and unlike most of the other festivals that are film-specific, this is also a television, music, and interactive media festival.
It's usually got some Sundance repeats along with new indies and a few big budget premieres. Films as different as A Quiet Place, Ready Player One, and Booksmart have all entered the world at the Austin-based fest.
The Tribeca Festival (previously Tribeca Film Festival, but the "film" was dropped as the event has expanded into other media spheres) has typically run in April in NYC.
Started by Robert DeNiro to revitalize lower Manhattan post-September 11, the festival is a celebration of indie film. This year post-COVID, it was moved to June, and became a launchpad for summer indies in addition to its competition and acquisition titles.