There are 2 ways of effectively doing this, in my mind.
1)- The montage.
What I would do with a montage is similar to what the First Spider-Man movie did. It was the scene after Peter assumes the responsibility of being Spider-Man. There are a number of shots showing Spidey thwarting crimes and saving the day in a number of different scenarios, only in my version, he would be battling super villains. You would see short snippets of him battling different foes, (mostly second or third tier,) utilizing some classic Spider-Man imagery. It would give the filmmakers an opportunity to feature a number of fan favorites without having to commit too much time, (up to and including the entire film,) on character development.
The downside to this method is that you don't get any character development, and you shortchange fans of said villains. Say Scorpion were used as one of the villains in this montage, and he were your favorite villain, you might be very disappointed, maybe even angry, if he got all of 5 seconds of screen time. This could potentially embitter a lot of people.
(CONTRIBUTOR'S NOTE: Having read this article several times over, I've realised that I didn't specify that the montage should be IN ADDITION TO whatever existing villain(s) and storyline are already being established in said film. It is not meant as the only means of visualizing antagonists. Sorry that I was a bit too vague.)
On to the next idea.
2)- The gang of puppets.
This use of multiple villains would work much more effectively, I think, and give multiple villains more screen presence without sacrificing precious screentime with excessive backstory and/or character development. The basis for this idea came from The Amazing Spider-Man issue 319, where Spider-Man goes up against the Scorpion, Shocker and Blacklash. Long story short, all 3 are working for Justin Hammer, and Spidey gets caught in the middle. On one page of said issue, Hammer has a screen with the images of a number of super powered operatives in his employ/debt.
Now, take this basic idea, substitute Norman Osborn (secretly) for Hammer, add the Tinkerer as a front man, and it could easily be used for a film. The storyline might play out roughly like this:
Osborn hires Tinkerer to create weapons to combat the emerging threat that Spider-Man poses to his interests. Tinkerer takes it a step further and integrates the weapons into suits. Then, he is tasked with finding people to wear said suits and battle Spider-Man. He does so, and POOF, you have a gang of super villains.
The benefit of using this concept is twofold: Firstly, you would get substantial screentime with multiple (tech based) villains. The plethora of fight scenes would be dazzling. Secondly, even though you've had little to no character development, what you have done is establish the existence of villains that can be brought back in future movies. You've also added a mystique to each of those characters that would leave audiences clamoring for a return of their favorite thug(s). The beauty of this is that you've given them a reason for being there without having to go into depth explaining it. Personal motivations for each character could be established in later films, if they were brought back.
Here are some villains that could be used for this venture:
Hobgoblin.
Rhino.
Shocker.
Beetle.
Scorpion.
Boomerang.
Constrictor.
These are just some of the many villains that could be used in this way. Any others that I missed that are your favorites? Post below.