Mewtwo Media
Art of Mewtwo Strikes Back Book

These weren't (and aren't) all that hard to find, but I remember procrastinating on picking this up on the longest time.
Mewtwo Strikes Back book

There were a couple versions of this. I still need to pick up the Golden Tales version, despite being a 3-year-old's rewrite.
Mewtwo Returns book

Sorry for the crappy photo on this one. I was suprised, given the lack of fanfare for Returns, that this still good a book adaptation.
MSB Comic #1/4

One of four comics. These are fairly common.
MSB Comic #2/4

MSB Comic #3/4

MSB Comic #4/4

Pokemon Yellow comic

This is one of the manga adaptations, I believe, where Blaine had much more to do with Mewtwo's creation than in other versions.
Mewtwo Strikes Back Press Kit

These used to be ridiculously difficult to find. They contain some info on the movie and a bunch of stills from it as well.
"I'm Not Pikachu!" Book

One of the many Pokemon Tales books for the young ones - basically everyone that goes to the first movie finds themselves turned into Mewtwos, Mews, and Pikachus. It was cute.
"Mewtwo is Watching You!" Book

This was another cute book despite how gruesome they made Mewtwo look at first. It was...interesting to say the least. I posted pics of each page on a message board a long time ago and everyone there came to the same conclusion - that it looked like Mewtwo was going to do some really messed up stuff to the other Pokemon, despite that not being the case.
Birth of Mewtwo Radio Drama CD

This was fairly difficult to find for a while, and got lucky to snag off of Amazon. It covers a bit of the history behind Mewtwo's creation - what SHOULD have been in Mewtwo Strikes Back...but I could spend pages ranting about how Mewtwo's character got misrepresented; I'll save that for another time.
Mastermind of Mirage Pokemon DVD

Random $1 find at a flea market in the area.
Mewtwo Returns Video CD

An uncommon find; while the DVD'd easy enough to find, I never thought we'd see a video CD of this. Weren't those obsolete by then?
Mewtwo Strikes Back DVD (Japanese)

Not much to say - common, but worth picking up just to have the subtitles.
Mewtwo Returns - Japanese?

Mewtwo Returns - Chinese?

Not sure if this is legit, actually.
Mewtwo Strikes Back - US DVD

Common, obligatory pickup.
Mewtwo Returns - US DVD

Sometimes I think I'm the only one that was waiting for a store to open to pick this up. They didn't even have it to scan in the system back then.
Mewtwo Strikes Back Clamshell VHS

I swear almost every thrift store is obligated to have one of these in the back somewhere.
Mewtwo Returns - US Clamshell VHS

Not complaining about this one showing up in a thrift store though - I wasn't even aware it got a VHS release by then (I only saw it available for DVD when I picked that up initially.)
Perfect Album

Mewtwo Strikes Back - GBA Version

I really should get another one of these and pop it into a GBA to see what it's like on there.
Worlds 2006 booklet

Tiny, almost inconsequential, but it's Worlds '06 so it gets a spot here.