Disney revealed titles, dates and descriptions of the last Ducktales Season 3 episodes. There are 4 episodes.
S03E19 Beaks In The Shell! 22/2
Huey struggles to keep Fenton and Gandra’s top-secret experiment (and their relationship) hidden from the world. But, Mark Beaks is desperate for one last gizmo to steal.
S03E20 The Lost Cargo of Kit Cloudkicker! 3/1
A new (but familiar) ally helps find treasure on an island full of monsters.
S03E21 The Life And Crimes Of Scrooge McDuck! 3/8
In a mystical karmic court, Scrooge’s enemies accuse him of making them evil.
S03E22 The Last Adventure! 3/15 90-minute series finale special
The future of adventuring hangs in the balance as the Duck family uncovers earth-shattering secrets in a final standoff with the Fiendish Organization for World Larceny (F.O.W.L.).
Also the reboot of Darkwing Duck now is in development.