You're thinking of Ash, who released a single every two weeks for a year, each signified by a letter of the alphabet. Only one of those charted though, Instinct.

 

Interestingly all of their releases prior to Record Store Day missed the top 100, but then after that almost all of them made the top 100 (only 2 of the last 13 missed out and both of them were only just outside). 'Instinct' was the only one to go top 75 though, must have been an abnormally low sales week. Shows Record Store Day had some sort of lasting impact.

Edited December 18, 201212 yr by Michael Bubré

Art Brut's top 75 chart career consists of four one-week hits (between 2004 and 2005) but that was a good find with Gorky's Zygotic Mynci, and they just beat That Petrol Emotion's most hits without going top 40.