That honor, of course, goes to what would be the eighty-fifth (canonically speaking) and final suit that Tony Stark ever built for himself.
His declaration that he is Iron Man before the fatal move would have been a beautiful send-off, if not for the message he recorded in case of “an untimely death” for Pepper Potts and their daughter Morgan (Lexi Rabe) using his helmet’s holographic recording device.
In addition to harboring the best upgrades of all the suits that preceded it, this model was used by Stark in Avengers: Endgame to make the ultimate sacrifice by crafting a makeshift Infinity Gauntlet with nanotechnology that could “snap” Thanos (Josh Brolin) out of existence.