1. Goblins' redesigns and how he could have looked:
This is an alternate costume that StudioADI created but Dafoe didn't like, so they changed it. There is a video on youtube about it (Check it out). And here you have more designs of how he could have looked.
One popular idea among the concept artists was to have the Goblin accompanied by adolescent women in costume and have their own gliders. Raimi hated the idea.
2. Sam Raimi had other plans with Spiderman 2
Initially, what Sam Raimi wanted for Spiderman 2 was completely different from what ended up happening. He wanted Spiderman to fight Doctor Octopus, The Lizard and Harry Osborn's green goblin but James Franco convinced him not to do that and only have Octopus as the viallain. Here is some concept art of how the Lizard would've looked:
3. Heath was one of the firsts choices for Peter
In a U.S. magazine tribute to mark the first anniversary of Ledger's death, CAA agent Steve Alexander reveals Ledger was among those considered for the blockbuster role before Tobey Maguire stepped up to play the comic book web slinger. Alexander tells Entertainment Weekly magazine, "Sony asked me to come over and read the script for Spider-Man. It was going to be a really cool tentpole movie. "But as soon as I said 'Spider-Man' Heath said, 'It's not for me. I would be taking someone else's dream away.'"
4. Rejected Black suit
One of the possible versiosns of the black suit for spiderman 3 was this one. Nobody really knows why it was rejected but rumours say that it was rejected because it was made of latex and spiderman looked like a porn actor.
5. Spiderman 4 poster
Did you know that Sam Raimi actually released an official poster for Spiderman 4 back in June 2009? The official date was May 6th 2011. This is the only real poster for the movie.
6. Schwarzenegger and Furlong as Octopus and Spiderman?
Did you know that James Cameron once wrote a treatment for the film and planned to direct? The rights to the franchise had fallen to Carolco Pictures, the same studio that made Terminator 2 and Cameron wanted to cast stars Edward Furlong and Arnold Schwarzenegger in the roles of Spider-Man and Doctor Octopus. However, Carolco ended up going belly up, and the rights eventually landed in the hands of Sony. They still had Cameron’s script and were eyeballing then “Titanic” star Leonardo DiCaprio for the role, before hiring Sam Raimi to take the reigns. He… had different plans.
7. Spiderman 4 storyboard
Spdierman 4 artist Jefrey Henderson revealed some storyboard for the movie.
8. John Malkovitch for Green Goblin
While Willem Dafoe delivered a spirited and powerful performance as megalomaniacal Norman Osborn in 2002's Spider-Man, one can't help but wonder what would have happened if über-creepy Malkovich hadn't passed on the role. Meetings were had and he was offered the part, but passed due to schedule and lack of interest
9. John Malkovich for Vulture
It was reported on December 8, 2009 that John Malkovich was in negotiations to play Vulture in the then-upcoming Spider-Man 4.[67] Malkovich himself confirmed the casting in January 2010.
Some concept art for the toys of the vulture was released. This is how he would have looked in the movie and in the toys:
10. Anne Hathaway for Black cat
Anne Hathaway was going to portray the Black Cat in Spiderman 4 but the funny thing is that she was also going to play as a made-up character called the vultress (although the vultress would've been Felicia Hardy).
Here is some concept art of how she would have looked: