Recently, there was an announcement that Sony will be making a Spider-Man spin-off film with Venom, which will not be connected to the bigger Marvel Cinematic Universe (MCU) or even Spiderman (which is a bad idea). This made me think of other Spiderman related properties and characters that might be better off having a Spiderman spin-off. There are quite a few, but I was able to cut it down to a few and if it were me, they would be included in the MCU.
Scarlet Spider is a very interesting character, as he is a clone of Spiderman created to destroy him but fails in doing so. Eventually he tries to discover who he is instead choosing to become a hero.
I chose Scarlet Spider because he has the most likely chance of seeing a Spiderman (like) TV/Netflix series, and there are many ways to do his story. Possibly having him escape the lab that created him, discovering that he and many other were created to kill Spiderman and trying to prevent it but has to go up against the other experiments. Who knows?
As for the character I think adapting him by fusing the various versions make him darker and more ruthless than Spiderman as he literally has all the powers but none of the responsibilities of Peter Parker.
Agent Venom (aka Flash Thompson) is a war veteran, who despite previously having lost his legs, jumps at the dangerous offer of being bonded to a weaker Venom symbiote. This would allow him to replace his legs enable him to walk again with the ultimate goal of working for the military as a super solider/agent. However, he cannot stay bonded to the Venom symbiote for more than 48 hours at a time, or the symbiote could gain complete control of him.
This character is very unique. He's an injured war veteran who gets back in the game using something that could corrupt him. It's a very interesting concept for a Netflix series and fits with The Defenders narrative that is currently being made.
Spiderverse: What Ifs
This is a very out there idea of mine but there are so many good Spiderman 'What If' stories that a mini series of Spider-Gwen, MIles Morales, Superior Spiderman and Silk would be so awesome. All of these Spidermen and women are great and all very different to Peter Parker, I think they'd be very fun to see on screen together at some point. Granted this would have to be outside of the MCU, it could still be used in a multi-dementional adventure like The Secret Wars.
The reason I put this last one in here is because of the rumour that Sony's 'Venom' won't be connected to Peter Parker's Spiderman, because Peter Parker isn't the only Spiderman there is. If they wanted to, Sony could create an 'elseworld' or 'what if' story using these characters.