First up, Viking Airlines of Sweden. Ended up going bankrupt because all the tour operators it flew for went bankrupt... They had three Boeing 737-300s and six -800s towards the start of 2010, the latter weren't particularly common at Manchester from memory, and I haven't yet found any photos of them.
SE-RHU | Boeing 737-36N | Viking Airlines by Chris Globe, on Flickr
SE-RHV | Boeing 737-36N | Viking Airlines by Chris Globe, on Flickr
Feel free to add your own, I'm sure there's plenty of airlines from the last couple of decades that no longer exist
