I believe there was some css magic script that would do basically this. But it would "simply" load every game page in the grid and look at the tags and then filter it out. Not very nice to the servers.
It would be a trivial matter to filter stuff that actually is on the browse page. Tags are not, unfortunately.
@-moz-document url-prefix("https://itch.io/games") { div.game_cell:has(a[href*="paste_full_link_to_game_inside_quotes"]) { display: none } div.game_cell:has(a[href*="//or_ignore_a_publisher.itch"]) { display: none } div.game_cell:has(a[href*="itch.io/or_ignore_games_starting_with"]) { display: none } }