All of the fanart they have received for Pokemon Green and other games they have played.
In Pokemon Crystal, the theme for the Radio Tower taken over by Team Rocket is similar to the Team Rocket Encounter theme (the encounter theme is shorter and higher pitched). Bert realizes this and decides to do something about it.
Bert and Dubz managing to defeat Whintney in Viet Crystal with a very tight plan, involving Steak leveling up and learning Curse just before her Miltank comes out and then sacrificing herself to use it, and a lot of luck with Miltank's attacks missing. And then the broken pokemon centerworks.
In Part 1 of their Superman 64 livestream, everyone had significant trouble just playing the game. Right at the beginning of Part 2, Dubz managed to pass the first level without missing a single ring and with 24 seconds left.
Bert added some NES Castlevania music to enhance their Criswelvania series.
For the last episode, he used remixes of the music instead.
And let's not forget how they ended it: Bert was Dracula the entire time.
After struggling on Road to Ruin, Bert finishes his "Odyssey" by breezing through Plant Food and obtaining the Yellow Gem.