Below are the best sites I’ve used for these sneak peeks.
IMDb
Quick access to trailers.
Huge database of movie information.

Provides the title’s release date.
It’s also simple to locate trending trailers and the most anticipated ones.
It’s one of the best sites for learning who played, or will play, in something.

FirstShowing.net
Release dates coupled with movie previews.
Reviews and other information on movies and actors.
Rotten Tomatoes
Easy to find trailers for movies opening this week.

Popular rating system from critics.
Includes news and movie trivia.
Scrolling through the trailers on this site is easy because they’re all on a single page.

you’re free to alsobrowse the trailers by when the film will be in theaters.
YouTube
Huge variety of trailers.
Lots of filtering options.

Also includes related interviews, reviews, and news.
No official page just for movie trailers.
Movie production companies and other users can upload movie trailers to YouTube that are free for everyone to watch.

ComingSoon.net
Has more than just movie trailers.
Multiple ways to find titles.
Several ads, including distracting in-video ads.

Search tool is unhelpful for finding just trailers.
Moviefone
Useful movie-related information.
Moviefone is an excellent source for all-things movies.
you might watch the newest trailers, trailers for movies coming soon, and those currently in theaters.
Apple TV
High-quality trailers.
Extra information beyond videos.
Only one way to browse.
Lists relatively few trailers.
Apple TV has trailers, too.
But the videos are high-quality and free from ads.
These trailers include a summary of the movie.