He's more than just a big man in a suit of armor, he is Iron Man (a.k.a. Tony Stark). Perhaps the most popular superhero in film right now, it was Iron Man who was primarily responsible for ushering in a "golden age" for superhero cinema.
While Mr. Stark couldn't have done that without his trusty Iron Man armor, he has proven time and again that he's quite something even without it. Apart from being the "biggest brain" in the MCU, he is (or was) also the de facto leader of the Avengers. His greatest invention, however, remains his legion of Iron Man suits. Among them, 10 stand out the most. They've become more than just armor; they have come to represent Iron Man at his finest.
MARK I
The progenitor and the granddaddy of all Iron Man armor. Tony Stark built this in a cave... with a bunch of scraps! Of course, he did it at gunpoint-- shows how much you can do under pressure. Let's also not discredit the fact that it looks like a homage to the old Iron Man armor of the comic books.
This suit goes to show just how far Stark has come, and is a far cry from what he was able to achieve later on. Take note of the highly vulnerable eyeslits on the helmet and the lack of computer. The Mark I was completely mechanical and had no digital interface. Regardless, it did the most important job of all the Iron Man armors: it saved Tony Stark and changed his life.
MARK III
Now we're getting somewhere. The Mark III is the first official serviceable Iron Man suit, which was built as a labor of love in an engineering lab (Tony's garage). It can fly, withstand high altitude, and has enough weapons to make whole armies drool. It was also the first suit to adopt the gold and red color schemes faithful to the comic book Iron Man.
Such an iconic and nostalgic Iron Man armor deserves to be higher, right? Well, based on how advanced or functional it was, we're not sure if Stark would even want to use this armor. It's worn like a traditional medieval armor and takes forever to suit up with it. While it is miles better than the Mark I (both of which appeared in 2008's Iron Man), it's still a bit impractical. Of course, from this point on, Stark kept improving his designs.
MARK V
The Mark V first appeared in Iron Man 2 and marks the first time that an Iron Man suit became portable. For those who missed that movie, the Mark V fit in a suitcase (or rather, it is the suitcase). This made Tony Stark's life a lot easier since from this point on, as he was able to become Iron Man anywhere.
It still wasn't perfect, of course. The Mark V, for all its flashy portability, appears to be less resistant or less durable to damage compared to the earlier suits which have thicker plates. Additionally, the Mark V has fewer combat capabilities than the heavier suits, since it had to be lighter for hand carrying in a suitcase.
JRXL-1000 (A.K.A. WAR MACHINE)
The JRXL-1000 Variable Threat Response Battle Suit is also known as the War Machine Armor Mark I. While it belongs to Stark's best friend Col. James Rhodes, it's actually a stolen Iron Man Mark II armor. Upon bringing it to the U.S. military and another weapons manufacturer, it was outfitted with better armor and conventional weapons.
You could say that War Machine was Iron Man on steroids, seeing that it had bigger and more explosive tools. Its most iconic weapon, however, is the back mounted minigun. It has an AI and targeting system of its own and can eliminate threats with 360-degree coverage.
MARK XLIV (A.K.A. HULKBUSTER)
As it turns out, there is no limit to what Tony Stark can do with engineering. The Hulkbuster is proof of that, demonstrating that even something as destructive as the Hulk also has its synthetic match. It first appeared in Avengers: Age of Ultron.
There is no question what the Hulkbuster is for: its purpose is taking down the Hulk (or keeping him busy at the very least). So, how did it fare against the big angry meanie? It was a success. The Hulkbuster proved capable of handling the Hulk at his most destructive moments... by the skin of Tony's teeth.
MARK XLII
It wasn't until Iron Man 3 that Tony was able to create a prototype of one of his most portable Iron Man armors. The Mark XLII or the 42nd Iron Man armor is an experimental wonder, whose problems were *ahem* ironed out throughout the third movie.
It's a complete and fully capable Iron Man suit which is also compact. Tony made it so that each part is modular with its own jet engine. This makes each part capable of flying and attaching to him separately until he is fully clad. The Mark XLII is also one of the first fully operable Iron Man suits that doesn't need an actual user inside. That's something Stark used again, as shown in Spiderman: Homecoming.
MARK XLIX (A.K.A. HULKBUSTER 2.0)
The Hulkbuster was a great invention and it would be a shame if it was only utilized once. Thankfully, Avengers: Infinity War saw another use for the Hulkbuster. This time, instead of fighting the Hulk, it helped him --or Bruce Banner, rather-- because the Hulk was missing in action.
It's worth noting that it wasn't Stark who built the Hulkbuster 2.0. The Mark XLIX was a modified Hulkbuster courtesy of Wakanda and Bruce Banner. Like the original Hulkbuster, it also fared exceptionally well. With it, Banner was able to defeat and kill Cull Obsidian, who was Thanos' most physically powerful minion.
MARK L
Speaking of Iron Man armors in Infinity War, Tony Stark also does not shy away from upgrades. His Mark L or 50th Iron Man armor featured a huge step-up in technology over any other suit he made prior. Instead of the clunky and cumbersome armor plates, the Mark L uses nanites or nanoparticles which can deploy all over Stark's body and manifest into an Iron Man suit. This makes it similar to Black Panther's suit.
While some might argue that it barely looks like armor, it certainly served its purpose well. It had all the capabilities of the previous Iron Man suits and then some. Not to mention, the Mark L was also more convenient than any predecessor. On a final note, we can recall Stark was able to use it to wound Thanos, Infinity Stones and all. He was the only Avenger able to inflict that kind of damage against the Mad Titan (A word of warning: the next two Iron Man armors are potential spoilers for those who have not seen Avengers: Endgame).
RESCUE ARMOR MODEL 1 (A.K.A. MK 1616)
We all know that Pepper Potts is Stark's soulmate in the MCU. They've been together through thick and thin. One could wonder why Stark never made her any Iron Man armor (even for emergency protective purposes) before. This gets rectified in Avengers: Endgame, when Tony gave Pepper her very own Iron Man suit as an anniversary gift. It's called the Rescue Armor Model 1 or MK 1616. Fun fact: 1616, when converted into letters, spells "PP," Pepper Potts' initials.
It's not just a mere gift, of course. Pepper used it for the final battle against Thanos in Endgame, in what appears to be a total geeky fan service moment which ought to put a smile on any Iron Man fan's face. It's smaller and more slender than Stark's suits, but still equally awesome and stylish with its blue and purple coloring.
MARK LXXXV
Stark's lfinal Iron Man suit is the Mark LXXXV or the 85th Iron Man suit featured in Avengers: Endgame. It appears to be a more metallic and bulkier version of the Mark L. What does set it apart from the Mark L (aside from appearance and upgrades) is the fact that it was also built to control and withstand the Infinity Stones. It's basically a portable Infinity Gauntlet-- the pinnacle of Stark's engineering.
Sadly, Tony died in this armor, after using the Infinity Stones to snap Thanos and his army out of existence. His heroic sacrifice saved not only the Earth but also the entire universe. Such a feat would not have been possible without the Mark LXXXV worn by the valiant Tony Stark.