Chuggaaconroy (found early Pokémon Platinum videos from YouTuber; 2008)
Since 2008, Emiliano "Emile" Rodolfo Rosales-Birou (a.k.a. Chuggaaconroy) has made a career doing Let's Plays (commentated walkthroughs of video games), and is currently one of the most famous internet personalities of the genre. Aside from regular playthroughs, his earlier videos sometimes consisted of one-offs, in which he would show single aspects of certain video games that caught his attention (i.e. cut footage from playthroughs, glitches, or limited edition DLC & offers). Among these one-offs was a series of low-quality videos showcasing events in the 2009 Nintendo DS game Pokémon Platinum. These videos consisted of "highlights" from the game, mainly battles against the in-game rival, gym leaders, Team Galactic (the game's main antagonists), the Elite Four & Champion Cynthia, and the Battle Frontier Brains.
Uniquely, the most well-known videos showcased a series of events that would allow one to encounter (and potentially capture) its various Legendary Pokémon, most notably Regirock, Regice, and Registeel. Said Pokémon were the secondary trio of Legendary Pokémon from the 2002/2003 Game Boy Advance games Pokémon Ruby & Sapphire and its 2005 re-release, Pokémon Emerald, and could only be caught in Platinum through limited-edition downloadable content.
At some point, the videos were made private, causing them to be visible to only a select number of viewers, and they were eventually deleted with no indication of potential recovery. While the exact circumstances of the videos' deletion is currently unknown, a probable inference would be that Rosales-Birou felt dissatisfied with the outcome and intentionally removed them. So far, the only video that has resurfaced was a mirror upload of his encounter with the pseudo-legendary Pokémon Rotom on August 6, 2011, by ChuggaaArchive; no other videos are known to have survived.