I like desolation the best out of all of them you will get at least 20 hours of content for the current version which is basically an average pokemon game. I think it has the best cast and story of any pokemon fangame I've played.
My signature pokemon for many years has always been Houndoom. I use it nearly everytime I play a pokemon game and it's very useful in reborn. Nasty plot can destroy slower teams with ease.