World of Warcraft. Ragnaros the Firelord kill from 2006.

I found a bunch of old videos from World of Warcraft's release including a defeating Ragnaros the Firelord for the first time, the opening of ahn'qiraj and a bunch of pvp events. If there is any interest I'll upload the rest. The videos are low resolution with very cheesy music but they show what the game was like at release.