IVA is a commercial site and you can’t browse around their database. Extras for TV shows is a feature request and been discussed before. Finding trailers for TV shows is probably possible, I’m sure there is someone gathering this. This new idea of “Coming up next week” is the wrinkle. To have this available for each episode would require a lot of active work by that source to make sure it is obtained in time. I just have not seen or heard of any place gathering this.
Edit - Don’t get me wrong. I like the idea, just not sure how realistic it is to make this possible,
