If the OP is looking for a club that is supporter owned with no rich person input then Exeter City are the perfect example as they are majority owned by their supporters trust. They won promotion to League One last season, are debt free, and 6 of their starting line-up in their first home game of the season were from the club academy (and a seventh, also the club captain, was on the bench).
Community involvement and supporter ownership are central to their model, as is developing young players to not only play in the first team but bring in transfer fees (Matt Grimes, Ethan Ampadu, Ollie Watkins to name just three).
Slightly different model, but Heart of Midlothian are basically funded by their supporters through their contribution model.
Greenock Morton FC in the Scottish Championship are also now majority owned by their supporter trust/fund if you're looking for a proper challenge.