By budget its usually the patreon people who are paying the dev(s) so there is no actual budget its more an ever increasing budget the longer the project it going on for
the trending tab lists all the most popular discussed games some very popular and others not so much, the latest updates section says what is most popular
in terms of content its tough to say because most games are still incomplete and only a handful of completed games are pretty popular so i would say its dependant on the dev and if he makes regular updates
Ones to consider are summertime saga ive played over 24 hours and have still yet to finish many storylines and treasure of nadia which is very content heavy