I'll kick this off with a band called Fightstar, formed by former Busted singer (most popular in the states for having one of their songs covered by the Jonas Brothers), who was dissatisfied with making pop rock and decided to make some alt metal/post hardcore in 2006. These guys would have been hits in the US during the emo/post hardcore explosion in the early to mid 2000s, but due to a lack of advertisement, they aren't as popular over here as they are in the UK.
Where Are They Now? Here's What Kyle Craven, Better Known As The Meme 'Bad Luck Brian,' Has Been Up To Since His 'Advice Animals' Fame