Mark I, II, & III

First appearance: Iron Man (2008) The first Iron Man film featured three variations on the armor starting with the hand-built armor in the cave. Tony’s Mark II in the film got the design and shape that would be the basis for the rest of the armors, but the Mark III is the slickest and most powerful of the designs. The Mark III armor is the first to use the red and gold color scheme and is used by Tony to defeat Iron Monger.
Mark IV, V, & VI

First appearance: Iron Man 2 (2010) Like the first film, Tony uses three new sets of armor throughout the film. The Mark IV is used when he attends the Stark Expo. It’s also the armor he’s wearing while drunk-fighting James Rhodes. The Mark V armor is influenced by the ‘Silver Centurion Armor’ and is the first set of armor Stark housed in a briefcase. The Mark VI armor was used by Stark to fight Hammer’s androids in the film’s finale. The cinematic version of the War Machine armor makes its debut in the film as well as an upgraded version of the Mark II.
Mark VII
First appearance: The Avengers (2012) The Mark VI armor from Iron Man 2 is what Stark uses through most of the film until he returns to Stark Tower and creates the Mark VII armor. The biggest improvement over this armor from the previous versions is its ability to seek out and form around Stark due to him wearing a homing bracelet. Director Joss Whedon also demanded the Mark VII have a circle arc reactor as opposed to the triangle in the Mark VI.
Mark XLII

First appearance: Iron Man 3 (2013) Following the events of The Avengers, Tony found himself in a state of constant depression and frustration and as a result built a startling amount of different armors. The Mark XLII was his primary armor, featuring a more golden color scheme than previous Marvel films.
Mark VIII-XLI

First appearance: Iron Man 3 (2013) All of the other armors between Mark 7 and Mark 42 also appear, with highlights being Heartbreaker, Deep Space, Godkiller, and Igor.
Mark XLIII
First appearance: Avengers: Age of Ultron (2015) When Avengers: Age of Ultron begins, Tony has a new set of armor, harkening back to his earlier sets of armor with the color and the circular arc reactor.
Mark XLIV

First appearance: Avengers: Age of Ultron (2015) Created by Tony Stark and Bruce Banner as a means of containing The Hulk, should that be needed, "Veronica" (a reference to Archie Comics since Banner's previous love interest was "Betty") was used by Tony to subdue Banner in Africa.
Mark XLV
First appearance: Avengers: Age of Ultron (2015) Following Jarvis' transition into The Vision, Tony created a new set of armor featuring a new AI named F.R.I.D.A.Y. Tony uses the armor for the film's finale, the Battle of Sokovia.
Mark XLVI
First appearance: Captain America: Civil War (2016) Inspired by the Bleeding Edge armor, Tony wears the armor for his bout with Captain America.