what are some pre 1935 9x19 handguns?

I can think of or quickly come up with
Walther Model 6, MP I, and AP.
Mauser Models 1909, 1912, 1912/14, Nikl Mauser (experimental).
Dreyse 1912
Lahti (models of 1935 but way off the evolutionary path of the big names.)
Gabilondo (Tauler, Ruby, Llama) I think made in 9mm P as well as 9mm Bergman.

The Glisenti (Brixia) auto will chamber and fire 9x19mm, but isn't safe with it. Likewise the Beretta M1923.

Radom model 35, designed before 1935 but most production was after 1935. Probably a more modern type of pistol than those mentioned above.

Astra Model 21, but issued in the more powerful 9mm Largo.

Walther MP...you mean the SMG?

Walther I...

That is one designation, "MP I."

Not the modern SMG.
In the late 1920s or early 1930s Walther made a few "MP" pistols.
They look like an overgrown PP in 9mm P straight blowback. Not strong enough in spite of a heavy slide and strong spring. The earlier Model 6 didn't work, either, but they tried again.

The collectors call it the MP I to differentiate it from the MP II, III, and IV which are ancestors of the HP and P38.