The Naked Gun 3 (I know that’s not the full title but I’m too lazy to change format), Return of the Jedi (warts and all), The Good, The Bad and the Ugly, In The Mouth of Madness (thematic trilogies, so we’re cheating here), Samurai III: Duel at Ganryu Island; and that’s all as far trilogies go. In longer franchises, there are much more.
I’d say Day of the Dead too, but there are other 3 films after it, perhaps we can regard those as a separate trilogy?