Yes, yes, I know, I post too much about the MCU, get over it. These are just ideas based on the rumored and announced movies coming up in the MCU: (Warning, there are spoilers, so if you haven't seen every Marvel movie since Thor 2, you should leave)
Avengers: Age of Ultron
Tony Stark has built Ultron, a robot designed to protect the innocent while the Avengers relax. While Stark is busy cohorting with the other Avengers, Baron Von Strucker gets to Ultron, and zaps him with Loki's Tesseract staff, possessing him. Ultron turns against the Avengers, and they flee Stark Tower before he can wound them. He ends up wandering around, and destroying entire cities in his wake. The Avengers gather as many allies as they can; the Falcon, War Machine, and two young supers named Quicksilver and Scarlet Witch. Ultron continues attacking major areas, and decides he needs a legion of his own, like Stark's Iron Legion. He steals Stark's, modifies them, and builds others. He makes one of them intelligent, and names it the Vision. He then decides his armor isn't strong enough, so he travels to the African nation Wakanda, where he steals mass quantities of vibranium to upgrade himself. He attacks the kingdom of T'Challa, the Black Panther in order to retrieve the metal. The Avengers begin to fight amongst themselves, partly due to Bruce Banner's temper. Banner hulks out, forcing Stark to don the Hulkbuster armor and fight Bruce. After the fight, Bruce gets incapacitated and put in a rocket, which gets set for space. The remaining Avengers then unite with T'Challa, and face off against Ultron, and finally defeat him, then recruit Black Panther and the Vision.
Mid Credits: Strucker laments over his failure with Ultron to a figure offscreen. The figure then angrily condescends him for his failure, and comes out of the shadows, revealing himself to be the Red Skull.
Post Credits: Thanos watches the events unfolding between the Avengers and Ultron, smiling at how easily they fall before the robot.
*Sometime before this, in a Planet Hulk or Guardians of the Galaxy movie, they should introduce Beta Ray Bill.*
Loki has used his false guise as Odin to gather an army of Storm Giants, but discovers they have no weapons, and he needs more allies. He resurrects the ancient fire demon Surtur, who makes new weapons for Loki's army, and agrees to assist him. Loki begins Ragnarok with Surtur's help. Thor discovers more and more about the cycle of Ragnarok, and finds out that it happened due to Those Who Sit Above in Shadow, and fights them and the Norns/Fates, and ends up severing the tapestry of Asgard's existence. During Ragnarok, several of Thor's allies and family are killed, and he goes after Loki. During a final fight, Thor decapitates Loki and keeps his head. He returns to Asgard, which has been reduced to rubble, where he finds out that this event was his father's plan the whole time. Thor exiles himself from Asgard, and on his way out, collides with a spaceship. He enters the ship to see who's inside, and is suddenly attacked by the occupant, Beta Ray Bill. Bill knocks Mjolnir out of Thor's hand, and lifts it, surprising Thor. The two fight, but Thor manages to wrestle the hammer back, knock Bill out, and leave the ship. Thor begins to fly toward Earth, but then decides not to, accidentally throwing his hammer to Earth, and he flies after it.
Post/Mid Credits: The hammer is lying on the ground on Earth, where it is picked up by a man named Eric. Eric Masterson.
Other Post/Mid Credits: Beta Ray Bill is chasing Thor, unbeknownst to him, to steal the Mjolnir for himself. He gets a message from Odin himself declaring him worthy of a hammer, and receives Stormbreaker.
*Another story could be Thor: The Living Planet, focused on the Behold the Living Planet storyline, and could involve Ego the Living Planet debuting, and manipulating the Midgard Serpent into fighting Thor at some point in the movie*
Captain America: The Fallen Son (Or Captain America: Civil War)
After the events of TWS, and the fall of S.H.I.E.L.D., Cap is questioning his country and his government. Due to the havoc wrought by the Winter Soldier, Ultron, and other super powered beings, the government has decided to pass a Superhuman Registration Act, requiring superheroes to reveal themselves to the public. Cap disagrees with this, and squares off with Iron Man over the issue. Cap then leaves the Avengers, and starts his own team, called the Secret Avengers, consisting of the Falcon, Black Panther, a mysterious new hero named Moon Knight, Ant-Man, (Scott Lang) and War Machine. Cap would be pursued by the now-scarred Brock Rumlow (Crossbones) and Taskmaster, sent after him by Baron Heinrich Zemo to kill him. He and the Secret Avengers end up in a battle with Iron Man & the other Avengers, Zemo's assassins, and various former agents of S.H.I.E.L.D. trying to carry out the registration act. After this battle, Cap surrenders and agrees to stand trial for his crimes against the Registration Act. On the way to the trial, Cap is shot by an unseen assassin. The shooter is revealed to be Cap's lover Sharon Carter, having been brainwashed by Zemo's forces. Bucky reappears, and vows to find the person responsible, as do Hawkeye, Black Widow, and the Falcon. Iron Man is left distraught, and goes into seclusion, temporarily.
Post/Mid Credits: Zemo is laughing over his success with killing Captain America, when a beaten and bloodied Crossbones falls through his door. Zemo looks up, and sees Bucky Barnes standing over Crossbones.
Other Post/Mid Credits: i haven't thought much about what the other credit sequence should be. I'll leave that up for you to decide!
(I had originally considered adding the Punisher as a Secret Avenger, but then thought Moon Knight would anger you enough, so I decided not to. Let me know if you think he fits, though!)
Alright, that's all. Discussion in the comments is COMPLETELY welcomed, in fact, I encourage it. But please, don't be a troll. Just be nice. Have at it!