I've only thought of three, Air Supply's breakthrough album, Bad English (one being a quasi-ballad, on the heartbreak side of things), and a 90's Celine Dion album. Uh, I guess Bryan Adams also had three, from Waking Up the Neighbours. I'm struggling with why there don't seem to be more from that 80's-to-early-90's era when singles were plentiful and ballads were reliably hits. Can you name any others (not necessarily from that time span)? Also, any ideas why that strategy hasn't been used more? Two of many possibilities I've thought of are singles sounding too much alike (Air Supply) and reputational damage (that's a batch of not well-respected acts).