Here are the four (out of a total of fourteen) Sherlock Holmes films starring Basil Rathbone and Nigel Bruce that are in the public domain. These may not be the most accurate adaptations of the Conan Doyle stories, but there’s a certain charm in these that I personally really love. Out of the four films below I recommend The Woman in Green the highest. The other three are OK, with Secret Weapon being a lot of cheesy fun as it’s literally a WWII propaganda film with Sherlock Holmes vs Nazi Germany. And if you decide to check out the non-PD ones, I’d recommend starting with The House of Fear and The Pearl of Death.
Sherlock Holmes and the Secret Weapon (1942)
https://www.youtube.com/watch?v=CsZQNdMKbNs - from the FEATURE FILM YouTube channel (1 hour 08 mins - 720p upscale)
Synopsis:
Sherlock Holmes and Doctor Watson must protect a Swiss inventor of an advanced bomb sight from falling into German hands.
Directed by Roy William Neill
Cast:
Basil Rathbone, Nigel Bruce & Lionel Atwill.
Trivia:
The fourth in the Basil Rathbone/Nigel Bruce series of 14 Sherlock Holmes films which updated the characters created by Sir Arthur Conan Doyle to the then present day. It is a spy film taking place on the background of the then ongoing Second World War with an original premise.
And the colourized version if you wish to dabble in such things:
https://www.youtube.com/watch?v=MylUEVqIAU4
The Woman in Green (1945)
https://www.youtube.com/watch?v=fypOpzikhDA - from the PizzaFlix Youtube channel (1 hour 07 mins long - 480p)
Synopsis:
Sherlock Holmes investigates when young women around London turn up murdered, each with a finger severed. Scotland Yard suspects a madman, but Holmes believes the killings to be part of a diabolical plot.
Directed by Roy William Neill
Cast:
Basil Rathbone, Nigel Bruce & Hillary Brooke.
And the colourized version if you wish to dabble in such things:
https://www.youtube.com/watch?v=fIvV20oFTFY
Terror by Night (1946)
https://www.youtube.com/watch?v=Ae5KnCP6QbI - from the PizzaFlix YouTube channel (59 mis long - 480p)
Synopsis:
When the fabled Star of Rhodesia diamond is stolen on a London to Edinburgh train and the son of its owner is murdered, Sherlock Holmes must discover which of his suspicious fellow passengers is responsible.
Directed by Roy William Neill
Cast:
Basil Rathbone & Nigel Bruce.
And the colourized version if you wish to dabble in such things:
https://www.youtube.com/watch?v=WBddAy-ZU-w&t=2483s
Dressed to Kill (1946)
https://www.youtube.com/watch?v=0qILka1Lz2U - from the PizzaFlix YouTube channel (1 hour 11 mins long - 480p)
Synopsis:
Sherlock Holmes sets out to discover why a trio of murderous villains, including a dangerously attractive female, are desperate to obtain three unassuming and inexpensive little music boxes.
Directed by Roy William Neill
Cast:
Basil Rathbone, Nigel Bruce & Patricia Morison.
And the colourized version if you wish to dabble in such things:
https://www.youtube.com/watch?v=0DFDrkAHqis