Impressed at closing plot holes [SPOILERS]

[MasterCat]

I'm quite impressed at how a shared universe encompassing 19 films and many writers continues to address hanging plot threads.
The two big ones I'm thinking of are Infinity War showing the Red Skull alive long after being teleported at the end of Captain America, and Iron Man's cryptic teases of a shared universe - Coulson telling Stark "This isn't my first rodeo" and Fury's "You think you're the only superhero?" - finally being explained by Captain Marvel after the Phase 1 films did in fact make it look like Iron Man was the first superhero since WW2.

So what loose threads might we still see dealt with in the future?
Has the Abomination been rotting in jail all this time? Did Samuel Sterns become an evil genius? (The Incredible Hulk)
What weapons has the US gov't acquired from the Hammer corporation since Iron Man 2? How long until national governments acquire hundreds or thousands of Iron Man suits (Stark told Congress Iran and North Korea were five years away, but he's a wisecracker)?
Does Advanced Idea Mechanics still exist after the events of Iron Man 3? Did the Ten Rings terrorist organization ever exist?
What's happened to Sif since Thor: The Dark World since her Agents of SHIELD cameo? The Russos say she was dusted, but that's irrelevant once the Snapture is reversed.
Will we ever see Norse realms other than Asgard, Nidavellir and, obviously, Midgard again? Where are Jotunheim, Vanaheim, the elf realms and the rest in relation to the aliens from other franchises?
What happened to the Pym particles that a Hydra agent walked off with (Ant-Man)?
How many sorcerers will Baron Mordo kill before coming to the notice of police or a superhero (Doctor Strange)?

 

[SPO2 Dalisay]

I Did the Ten Rings terrorist organization ever exist?

Do you mean where the Ten Rings under the leadership of a "real" Mandarin? Or where they merely another wing of Hydra whose members like a different tattoo in Ant-Man? In Iron Man 3 my guess is that like the Mandarin the actual terrorist where AIM extremis subjects masquerading as the Ten Rings.

 

[MasterCat]

Do you mean where the Ten Rings under the leadership of a "real" Mandarin? ... In Iron Man 3 my guess is that like the Mandarin the actual terrorist where AIM extremis subjects masquerading as the Ten Rings.

Yes. Were the Ten Rings a real terrorist group with a "real" Mandarin, a terrorist group motivated by a real ideology but created by Eldritch Killin as a front, or AIM subjects/actors?

 

[Orba]

Yeah the Ten Rings are real, they are the group that grabs Tony in the first Iron Man, in a deleted scene from Iron Man 2 a character listed as being from the Ten Rings gives Whiplash the tickets that gets him to Monaco. In IM3 AIM just performed identity theft on an existing terrorist group to cover up that the explosions were accidents by having their version of the Ten Rings claim responsibility for the explosions. The 'Hail to the King' one shot confirms that the Ten Rings still exists and that their is a real Mandarin.

 

[Random490]

As far as we know Abomination is still in his cell. There were early plans to have him appear in the opening of Age of Ultron it never moved forward.

I believe it's implied that the Ten Rings were a terrorist organization that was secretly founded and supported by AIM, using the myth of the Mandarin as a figure head. Presumably they still exist in a more limited capacity now that a large chunk of the organization is gone due to AIM falling and with someone claiming to be the real Mandarin.

There was actually a scene that was cut were they recovered the unaccounted for pym particle but decided to leave it open for the future.