I discovered gazillions of movies on Imdb, actually it's my primary resource. Through either the "more like this" carousel on a movie, or by filtered search (eg. best rated 50s comedy with at least 15k reviews).
@OP: Maybe just finding a way to curate the most popular open source libraries into lists per language, framework, etc would be helpful? For example, for me I'm not particularly interested in all open source projects, but I'm really interested in Django stuff. Hence why I love looking at the awesome-django curated list [3]. Maybe an application to just rank all packages for a given ecosystem? Just spitballing.
[1]: https://www.imdb.com/chart/top/ [2]: https://www.imdb.com/search/title/?title_type=feature&genres... [3]: https://github.com/wsvincent/awesome-django
Was thinking this "ossdb" could work similarly.
TLDR you can't always trust reviews (or peoples tastes). If the Trailer & synopsis hooks ya why not give it a shot when you can always just stop watching if it doesn't pan out.
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Now as far as an IMDB for open source, I'd say maybe even go so far as doing a Letterboxd type deal? When it comes to opensource projects it always helps to hear what the users are saying about it.