During the Credits
There are multiple extra scenes during the credits of Aquaman.
The second scene shows the news media reports of mid-sea disturbance with scientists unable to convince the world of Atlantis being real.
Dr. Stephen Shin appears to question Manta about his suit. Manta agrees to help Dr. Shin find Atlantis, provided he first helps him find Aquaman, as the scene ends with him throwing a knife towards an anonymous picture of Aquaman.
After the Credits
There is no stinger after the credits of Aquaman.
Special thanks to @F3tjang, Pablo Ibarra, JFlawyer44, Dr Linda Hamzah, lewis, Mafalda Gil, and Vinuffy for the stinger submissions!