Insurgence brought in my opinion a new feel to the game with the cults and all
Reborn is the one that started it all, after it was made other games started showing up and each one was better then the last, the plot the story, you can actually play a game and feel really involved
Rejuvenation is i would like to think Reborns younger sister, and i love everything about it, the plot espacially the grand dream city ark of episode 9 witch was mindblowing, really great storyline
Desolation was just an ok game for me when I first heard of it then I started palying it and the choices that you made effected the game drastically, sometimes I would find myself thinking about 10 minutes before actually choosing
Phoenic Rising i heard a lot of great things about it and people also have said that it will be the greatest pokemon fangame, but everyone has their own opinions cant wait for its completion
And these are the main ones in my eyes but if ur looking for a complete game theres always Uranium (fantastic plot) but if u are not really a fan of fakemon theres pokemon zeta/omicron another work of Suzerain the creator of Insurgence and while theyre a bit too plain in my opinion theres 80 hours of playtime in there and theres optins as randomizer, nuzlock and more that can spice up the game for sure