A few things to note: no X-Men or Fantastic Four members are featured. So, it seems the Fox characters haven't been brought into the licensing fold.
That said, there is an introduction page that mentions how Stan loved alliterative names, and they list Reed Richards, Sue Storm, Doctor Doom, Scott Summers, Warren Worthington, and the Silver Surfer among the examples (though, as a Fox character, the Surfer doesn't appear in the calendar, either. Same for Doom).
They also make a reference to the omniverse/alternate realities, and state the characters within are on Earth 616, or the "Prime Reality". Bleh.
The Inhumans are all over it. Daredevil, Power-Man, Iron Fist. Of course, Iron Man, Hulk, Captain America, Thor, Hawkeye, Black Widow, Black Panther, Ultron, Ant-Man, Wasp, Dr. Strange, Valkire, Loki, Hela,Thanos, Dormammu, The Red Skull, Baron Zemo, Arnim Zola, Doctor Octopus, Ghost Rider...
All very classic images. From the ealry 60's to the late 80's. The most recent character and drawings are of Venom (because Marvel and Sony are cool, now, I guess) and Rocket Raccoon. None of the other movie Guardians seemed to have made the cut.
Maybe it's because people love animals...or animal-looking beings, anyway. Lockjaw is featured quite often. Or could that have to do with at the time the calendar was being made, they perhaps thought The Inhumans were going to be the Next Big Thing? Oops.
Also featured prominently: She-Hulk, Spider-Woman, The Enchantress, Nova, and MODOK. I see the first two on a lot of newer licensing...makes me wonder what the plans for the characters are.
Who'd have thought we'd get to the point where we see a Marvel calendar without the Thing or Wolverine...but with Karnak??
Also missing: Captain Marvel. Any version. No Mar-Vell, no Monique Rambeaux, no Carol Danvers, (No Billy Batson). Seems odd, as this is a 2019 calendar and that's supposed to be her year. But I guess they were going "vintage", but also didn't want to confuse things with any of the others. Yet, Thanos has several "days"...(because he is the Big Bad of the MCU).
It's film and TV "favorites" represented by artwork that predates any of the movies or shows by decades. But, that's kinda been Marvel's jam for the last ten years, I guess.
Some gorgeous stuff in there, though.