Gypsy was originally the lead single for Artpop until about halfway through development of the album. I think it was the owner of Operation Gaga that confirmed that. It could still be a single though.
Katy Perry - Hummingbird Heartbeat
Christina Aguilera - Let There Be Love
Christina Aguilera - I Hate Boys
Christina Aguilera - Impossible
Shakira - Hey You
Shakira - Why Wait
Azealia Banks - Esta Noche
Alicia Keys - Put It In A Love Song
Some of the ones y'all are listing actually ARE singles, n. They just flopped / weren't promoted.
Hey You & Why Wait were NEVER singles
LTBL was only a vid for fans, IHB only a digital single in Australia & Impossible was cancelled for TVW
it was supposed to be released as the fourth single off of "When the Sun Goes Down", they even got Flo Rida to record a verse for the remix, but it was never released
...but Starstruck and Scheiße were never confirmed as planned singles. Out of the list you have for Gaga, Venus was the only cancelled single. (Hopefully it's just postponed though, as I'd really like to see it as the final single of the album.)
Wasn't Boys, Boys, Boys supposed to be the end of The Fame?
No, not the end. Just the next one - I have a feeling TFM was supposed to have been a full album in mid to late 2010 but Gaga rushed it because she was confident in the material.
Pink - 18 Wheeler
Kelly Clarkson - Gone
Kelly Clarkson - Sober
Kelly Clarkson - You Thought Wrong
Lindsay Lohan - I Live For the Day
Lindsay Lohan - Fastlane
Hilary Duff - The Getaway
Kelly Rowland - Gone
Kelly Rowland - Every Time You Walk Out That Door (announced on TRL)
Kelly Rowland - Feeling Me Right Now (video was planned)
No Doubt - One More Summer
Britney - Boom Boom, Breathe on Me
...but Starstruck and Scheiße were never confirmed as planned singles. Out of the list you have for Gaga, Venus was the only cancelled single. (Hopefully it's just postponed though, as I'd really like to see it as the final single of the album.)
There's a snippet of a clip of the 'video' in this commercial: