Spoiler:
Guardians of the Galaxy Vol. 2Laura Haddock is returning as Meredith Quill, Star-Lord's mother. Sylvester Stallone is credited as "Chief Centurion" Sharon Stone is credited as "Balthak"
Spider-Man: Homecoming
Logan Marshall-Green is credited as "Bryce / Shocker #1" Bookem Woodbine is credited as "Schultz / Shocker #2" Donald Glover is credited as "Farrell" Tyne Daly is credited as "Hoag" Gary Weeks is credited as "Porter" Hill Harper is credited as "Cleary" Christopher Berry is credited as "Ballinger / Goon #2"
Thor: Ragnarok
Zachary Levi is returning as Fandral, Thor's friend. Sam Neill is credited as "The Trader" Josh Brolin is appearing as Thanos.
Black Panther
Andy Serkis is returning as Ulysses Klaue William Hurt is returning as Secretary Thaddeus Ross Letitia Wright is credited as "Suri" Malachi Kirby is credited as "Young T'Chakka"
Ant-Man & The Wasp
Judy Greer, Abby Ryder Fortson and David Dastmalchian are returning as "Maggie", "Cassie" and "Kurt". Negotiations are underway for the returns of Bobby Cannavale and T.I. as "Paxton" and "Dave". Casting is underway for Janet Van Dyne, described as "a heroine from the past". Michelle Pfeiffer is in early talks. Casting is underway for Elias Strickler, described as a "mad genius". Christopher Waltz is wanted for the role. Casting is underway for David Cannon, described as a "ruthless enforcer". Kevin Durant is wanted for the role, but auditions are expected to take place. Casting is underway "Eric O'Grady", described as "an opportunistic con man". A comedic actor is being sought for the role. Casting is underway for Harrison Shepperd, described as a "relentless government agent". Older actors are being sought for this role. Both Jeremy Renner and Anthony Mackie are slated for appearances as Hawkeye and Falcon.
Captain Marvel
Although supporting characters are still being refined due to ongoing script revisions, casting calls are being prepared to cast the five key-roles aside from Brie Larson's Carol Danvers: "Monica Rambeau", "David Lawson", "Karla Sofen", "Ian Taggart" and "Yon-Rogg". Yon-Rogg has priority casting as he is due for a minor appearance in AVENGERS 3 / AVENGERS 4. Joel Edgerton is the frontrunner.
Avengers 3 / Avengers 4
They're being filmed back-to-back, therefore the casting developments for both are happening simultaneously. Unsurprisingly, all mainline heroes from the MCU are expected to make appearances. The plan is for all notable characters involved in the previous movies to make special appearances, including notable characters such as Pepper Potts and Jane Porter, whose actors's fulfilled their original contracts. The arrangement is for these cameos to be done out of goodwill, without requiring the renegotiation of a new contract. The supporting characters expected to make notable appearances throughout the two movies include Peggy Carter, Thaddeus Ross, Maria Hill, Hank Pym, Janet Van Dyne, Wong, Zuri, Loki and Odin. Eva Green is in final talks to play Lady Death. Casting is underway for Eitri, "the creator of the Infinity Gauntlet". Peter Dinklage is in negotiations for this role. Casting is underway for Corvus, "Thanos's vicious right-hand man". This role will require substantial prosthetics/mocap. Casting is underway for Nox, "a loyal follower of Thanos". This role will require substantial prosthetics/mocap. The character is named "Black Dwarf" in the comics. Casting is underway for Ican, "a loyal follower of Thanos". This role will require substantial prosthetics/mocap. The character is named "Supergiant" in the comics. Casting is underway for Proxima, "a loyal follower of Thanos". This role will require substantial prosthetics/mocap. Casting is underway for Ebony, "a loyal follower of Thanos". This role will require substantial prosthetics/mocap.