This is the first one that came to mind as I just learned this:

Marx was not the first to do a class analysis. His analysis wasn't even accurate and well-defined. It was bogus.

French radical liberals Charles Comte and Charles Dunoyer did it before him and more accurately. They divided society into the productive class (industrialists) and unproductive class (parasites).

https://www.libertarianism.org/articles/libertarian-class-analysis

The former acquires wealth by producing and cooperating (entrepreneurs, workers, labourers, investors).

The later does so by stealing and coercing (State, bureaucrats, thieves, cronies).

This analysis is essentially libertarian in spirit.

Many liberals use Marxist class analysis rather than that of Comte and Dunoyer and come to the wrong political conclusions that go against their core philosophy.