Leaving aside the double A-sided singles, I particularly like "Revolution," "I Am The Walrus," "Don't Let Me Down,""Rain," and "Things We Said Today." I think that singles outsold albums until the late sixties, so maybe putting a good (and perhaps not particularly commercial) song on the flip was considered a way of featuring it. By the seventies, it was very much an album-oriented market, with singles (and usually only the A-sides) serving as radio trailers for new LPs, but the perception of the relative value of a B-side may have been a lot different in say, 1966.
.... though John and Paul did fight a lot over who got the A vs B side, IIRC reading ...
To make things complete: the UK singles listLove Me Do / PS I Love YouPlease Please Me / Ask Me WhyFrom Me To You / Thank You GirlShe Loves You / I'll Get YouI Want To Hold Your Hand / This BoyCan't Buy Me Love / You Can't Do ThatA Hard Day's Night / Things We Said TodayI Feel Fine / She's A WomanTicket To Ride / Yes It IsHelp! / I'm DownWe Can Work It Out / Day TripperPaperback Writer / RainEleanor Rigby / Yellow SubmarineStrawberry Fields Forever / Penny LaneAll You Need Is Love / Baby You're A Rich ManHello Goodbye / I Am The WalrusLady Madonna / The Inner LightHey Jude / RevolutionGet Back / Don't Let Me DownThe Ballad Of John And Yoko / Old Brown ShoeCome Together / SomethingLet It Be / You Know My Name (Look Up The Number)
To this day, I'll never understand why Back in the USSR wasn't a single off the White Album with something like Happiness is a Warm Gun or maybe I'm So Tired as the B-side. I know Paul wanted Ob La Di Ob La Da as a single but was vetoed....so it's not as if the idea of a single wasn't floating around. USSR would have been perfect.