Spider-Man started swinging over the streets of New York City in the early 1960s, and since then, he's mostly been something of a loner. Sure, he's friends with Johnny Storm, and he's had a team-up or two over the years, but most casual fans wouldn't think of Spider-Man as the type of superhero with a sidekick.
As it happens, ole' Web-Head has had more than his fair share, but unlike Batman, he doesn't keep them around for very long. Also, the Peter Parker from Earth-616 isn't all about having someone swinging around with him (who isn't Mary Jane), so most sidekicks hail from alternate universes or fill specific roles for a short time.
Fortunately, the Marvel Multiverse is filled with all manner of Spider-Men, and many of them didn't turn away their version of a "Boy Wonder" when they came calling. As a result, there are tons of superheroes who took to the rooftops with Spider-Man, and many of them found a close association with their version of Spider-Man.
There are also characters in the regular Marvel Universe of Earth-616 who could be called a sidekick, if only for a short period of time. Of the many characters who could call themselves as such, these ten are the ones most people forgot ever swung with Spider-Man.