1. Pym Particles
Ant-Man (the original one) invented something that alters the distance between atoms. That means he can make things grow or shrink. This has a wide range of applications if you use your imagination. Even when used incorrectly the particles reduce the subject to a bit of goo. In other words, Pym particles can atomize any threat. Ultron? Pile of goo. Thanos? Pile of goo. Additionally, Pym explains that the mass of a subject is preserved as the size of the subject shrinks, allowing Ant-Man to “punch like a bullet.” This bit of movie-physics is also the only sciencey way the next magical item could realistically function.
Appearing during Malekith’s invasion of Asgard in Thor: The Dark World, these weapons were never named, but if they were, the most obvious name would be “black-hole grenades.” Black holes are the great equalizer in comics and sci-fi because they can crunch pretty much anything. I’d argue that if Malekith can mass produce portable, on-demand singularities, then he really doesn’t need the much sought after Aether.
3. Gamma Radiation/Bruce Banner’s blood
Reproducing what happened to the Hulk or using Bruce Banner’s blood to reproduce what happened to Emil Blonsky in The Incredible Hulk results in either a Hulk or an Abomination. Sure, they aren’t exactly controllable, but the ability to recreate the strongest beings in a universe that includes literal gods earns the number three spot.
4. A Bunker of Iron Men
Iron Man is debatably the most powerful Avenger because of his armor alone. Tony Stark can make a lot of that armor and automate them all. It’s not a stretch to say that five Iron Men could defeat any five Avengers. Tony detonating his bunker o’ armor in Iron Man 3, was the biggest waste of military might in movie history…until, debatably, the detonation of all those helicarriers in Winter Soldier. Those taxpayers should be pissed!
Here we have a bio-tech enhancement that (a) makes you a regenerating superman who can breathe fire or (b) makes you overheat to 3000 °C and explode. The living bomb angle works if it’s not you that’s doing the exploding and your motivations are generally evil, but the real usefulness is obviously (a). This could be ranked a couple spots higher if it showed more consistency in the (a) space. Maybe Extremis 2.0 has a shot.
6. Yondu’s Whistling Arrow
Yondu, the guy Star Lord worked for in the first act of Guardians of the Galaxy, has this little pointy thing that he controls with his mind and/or whistle. It kills a bunch of armed guys quicker than Thanos probably could. This begs the question, why wasn’t Yondu the heavy of the movie?
Vibranium is the strongest material to which Marvel Studios has movie rights. It’s great for shields, helicarriers, and iPhone cases.
8. Super Soldier Serum
They had the means to create Captain America out of a weakling in the 1930s. I imagine they could figure that out again and maybe improve the formula in the following several decades. When they start with a guy who isn’t already chronically weak, like they did in The Incredible Hulk with the aforementioned Emil Blonsky, they are off to a better start.
A better version of Siri would benefit us all, and I’m not talking about Cortana.
I had to include this because, technically, it’s a god-maker. That said, it is too niche an item to be high on the list. It can only be used by the worthy and, let’s face it, that’s not you nor I. Only Thor (sometimes) and Vision have had the honor. If we look at the hammer pragmatically, it’s just the world’s most effective paper weight.