HSS have the Mercedes W25, the Bugatti T59 and the Auto Union Type A from 1934.
Paid
Patreon only, while they're in early access.
They also have a Alfa Romeo Monoposto (aka Tipo B, P3 yada-yada) free on
SimVendor. The model is different to
@GzeroD 's car (narrower) and altho it's labelled as a 1934 (and skinned from 32-35), I suspect it might actually be the skinny-er 1932/3 Formula Libre version.
"For 1934 the car was upgraded with a 2.9 litre engine and wider bodywork to conform with the 750 kg formula."
~ Golden Era
The change was from 65cm to 85cm apparently, which seems to align with the differences in the models.
Whatever the truth, the mod has improved hugely along it's path to 1.0, and is well worth a look.
And now that I'm looking, I see that the Bugatti T59 has reached ver 1.0, which is when HSS traditionally releases cars for free on Overtake or SimVendor.