Not sure if this thread has been done before but
Tony Yayo had T.I.'s "What You Know About That" beat first
T.I.'s "Bring Em Out" was supposed to be Beanie Sigel's first single home from jail (that's why Swizz chose that Jay-Z sample) but Beans passed on it
Jay-Z "Blue Magic" was meant for Yung Joc
Ludacris's - "The Potion" was meant for Jay-Z
50 Cent - In da Club was meant for Rakim first, then D12, and both passed on it
Hurricane Chris "Halle Berry" was meant for Dorrough lol
Rick Ross "BMF" was meant to have a Jay-Z verse but he accidentally emailed it to Styles P
Plies & Keri Hilson "Medicine" was meant for Gucci Mane
Not hip hop, but Britney Spears "Hit Me Baby, One More Time" was meant for TLC
Keep it going!

Tony Yayo had T.I.'s "What You Know About That" beat first
T.I.'s "Bring Em Out" was supposed to be Beanie Sigel's first single home from jail (that's why Swizz chose that Jay-Z sample) but Beans passed on it

Jay-Z "Blue Magic" was meant for Yung Joc
Ludacris's - "The Potion" was meant for Jay-Z
50 Cent - In da Club was meant for Rakim first, then D12, and both passed on it
Hurricane Chris "Halle Berry" was meant for Dorrough lol
Rick Ross "BMF" was meant to have a Jay-Z verse but he accidentally emailed it to Styles P

Plies & Keri Hilson "Medicine" was meant for Gucci Mane
Not hip hop, but Britney Spears "Hit Me Baby, One More Time" was meant for TLC
Keep it going!