Cool thread! Although it was hard to pick a top 5.
One that immediately came to mind were the Amada stickers. The artworks on these, especially the Amada Attack ones, are among my favorites.
Team Rocket Rubik’s Cube. As someone who collected twisty puzzles in the past, it’s cool to have an item that combined both those collections. 
There are a lot of cool Seviper figures, but my favorites are defintely the XO Studios ones. They look amazing.
The Greek (and Polish) Metal Tazo. As someone who collects all languages for the TCG, it’s cool to have a non-TCG item in a language that isn’t available in the TCG.
And although they’re also a bit annoying, I like that the Kraks is available in many different colors to collect. I hope I one day be able to have all 15 colors for Seviper (I’m currently sitting at 12; with one additional Seviper Kraks from the second set).
Greetz,
Quuador