Tiffany Richardson, Jaslene Gonzales, Marvita Washington, Kacey Leggett and Angelea Preston were, respectively, casting week rejects of Cycles 3, 7, 9, 11 and 12 before making it as finalists for Cycles 4, 8, 10, 15 and 14 (and 17 for Angelea).
Cycle 9 winner Saleisha was featured in Cycle 6 as a working model. This, coupled with her participation in Tyra's modeling camp, caused controversy to her win.
Isis King was an extra in Cycle 10's first photoshoot before making it as an official contestant in the next (and 17th) cycle.
Nole Marin guested a few times in Cycle 2 before joining the panel in Cycles 3 and 4.
Too Soon: Twice in the course of the show, there have been situations where one of the contestants was given news that a close friend had died, and then had a shoot involving death soon after. In Cycle 4, Kahlen was given the news, then had to play the Deadly Sin of Wrath, in a coffin. Then, in Cycle 8, Jael was informed a friend passed away, then had to play a murder victim soon after.
What Could Have Been: The (potential) contestants of the All-Stars Cycle represent this trope in spades.
Apparently, Cycle 3's Toccarra Jones, Cycle 6's Jade Cole and Cycle 10's Lauren Utter were asked to return in Cycle 17. Neither did, thus explaining why Cycles 5 and 11 had two representatives.
Cycle 7 runner-up Melrose Bickerstaff wanted to take part of All-Stars but her agency didn't allow her to.
The All-Stars Cycle had a non-elimination week in episode 5 with Lisa and Angelea in the bottom two. The two became finalists with the former ultimately winning.