Everybody knows about Main Characters and Protagonists but can you think of any works (books) where it really was an ensemble of characters that you fall in love with and drives the book instead of just one MC?
I noted this more in series fiction as a child - The Babysitters Club, Sweet Valley High (a lot of girl gang fiction) but as I got older some genres utilized this format. One was a trend in the 90s/90s to recreate night soaps. Sex & business fiction. They would have like five shifting storylines rather than one person to route for. Anytime you can gather a group together either for a common goal or separate goals it can work. I seem to recall Shirley Conrad being very good at this.
I think for an example of characters to work the way you're taking about it's best to use an omniscient POV.
Yep. Better, imho. Especially when the rotating POV shift is cleanly and solidly chapter-by-chapter. It forces you to give every character his/her moment on the stage. The books I posted above are like that.
Also some Stephen King books like 'It' and a few of his other works. Although they do sometimes have one character who gets more focus, all the main people get a chapter or two to themselves. And some children's books like Famous Five, I think, did this.
Lord of the Rings is the first one that pops into my mind. The Bakemonogatari light novels are also an awesome example of a huge cast of characters done remarkably right. Although they still follow the adventures of a single protagonist, it's the side characters and his interactions with them that really make the series.
'IT' was one for me I felt like the book wouldn't have been a good for me if just one of those characters were missing. Oh, and Jurassic Park, plus I loved the very relevant themes in that book. They were relevant over 20 years ago and they still are today so it's timeless.