thefader.com #RIHJECTS: 14 Songs Written For Rihanna That Other People Recorded A recent history of the tracks Rihanna passed on.

and because not everyone knows how to share playlists as playlists yet
Someone needed to step in. Thankfully, Bas did.

NPR's planet money dug deeper into what it takes to write a Rihanna song.
tis interesting yalls, and kinda explains more why she has so many leftovers.

npr.org How Much Does It Cost To Make A Hit Song? We go step-by-step through the making of Rihanna's song "Man Down." Bringing in top songwriters and producers costs tens of thousands of dollars. Trying to turn the song into a hit costs much more.

Edit

According to the internet, the following songs were also rejected by Rihanna: 

• Ed Sheeran – Shape of You
• Major Lazor – Lean On
• The Chainsmokers – Don't Let Me Down
• Sia – Cheap Thrills

and some other ones. Here's an updated playlist to include those tracks as well.