I still haven't played the last two ranger games oops. I did have a time when I planned on it but I never got them so oh well. There are other games I would rather save up and get than the ranger games right now so who knows if I'll ever play them.
The Ranger spin-offs are among my least faves; I couldn't even finish the third because I had gotten bored with it :< (That being said, I have been tempted to try the second one again, as I found that one to be the most enjoyable of the three.)
I own/have owned most of the spin-offs that were localized XD Snap (on my Wii), both Pinballs (one was my cousin's; I returned it to her and gave her the other), Puzzle Challenge, Colo & XD, every PMD game that was localized, every Ranger game (all sold), Conquest, Rumble, Rumble Blast (sold), and Battle Trozei. I've also played Stadium & Stadium 2, Puzzle League, the TCG video game, Channel, Battle Revolution, and a little bit of the original Trozei, ahaha. I plan on adding Art Academy and maybe that Detective Pikachu game--if it turns out to be any good--to my collection. So many spin-offs, pft.
Out of the spin-offs I've played (of the top of my head) Pokemon Stadium 1/2, Pokemon Snap, Pokemon Puzzle League, Pokemon TCG, Hey You Pikachu (only very little of it though), Pokemon Colosseum/XD, Pokemon Ranger, Pokemon MD (Sky and GoI), aaand Pokemon Channel. I really really want Pokemon Art Academy though aaah. And maybe that Pikachu Detective Game too.