I've seen shows rated higher than some of the shows listed not make it on the list, and this confuses me. For example, one show that's rated 8.4 by the users is not on the list, despite shows rated 8.3 and lower making it on the list.
Make sure you're reading the footnotes at the bottom of the Top 250 page regarding what is eligible and how the ratings are computed. https://www.imdb.com/chart/toptv/