Genre 

"Heavy Metal" simply isn't enough to describe early Black Sabbath. According to this, they originally formed as a blues-rock band, and according to this, VH1 calls them "Hard Rock." I think that's more than enough evidence that either "blues-rock" or "hark rock" need to be added to the genre section.  talk  James Bond 
I assume that you want to add to the infobox because these other genres/subgenres are mentioned in the article. This comes up frequently on this page, and the problem is that bands with long histories can be categorized under many different heading, in this case, the ones you mentioned plus, doom metal, stoner rock, gothic metal and others are often brought up. To keep things under control it has been decided that it would say 'Heavy Metal' in the infobox (because there are the most sources calling them that) and 'Rock' in the opening sentence, because all of the other genres are subgenres of Rock. The 'Formation and early days (1968–1969)' section of the article talks of their blues origins and other styles/genres are described in the 'Musical style', 'Legacy', and 'Influence and innovation' sections of the article. (talk page)