I attended to lectures recently at the Vancouver Institute.
https://globalreportingcentre.org/vancouver-institute/Professor Sylvia Nasar mentioned the liberal political economist Alfred Marshall as 'the founder of modern economics, and the greatest economist hardly anybody has ever heard of.'
Professor Sander Gilman mentioned Isiah Berlin who took Emanuel Kant's idea of 'crooked timber' and ran with it. Isaiah Berlin has been called 'the last great liberal philosopher.' Again, he seems to be largely unknown.
Both Alfred Marshall and Isaiah Berlin tended towards moderation, opposed easy solutions and opposed scapegoating and demonizing.
The only famous great modern liberal thinker I'm aware of is John Maynard Keynes (a contemporary of Berlin) and he seems to be known because his ideas were taken by those further to his left as a justification for jobs financed by government deficit spending no matter at what point in the 'economic cycle.'
I don't know that it's accurate to say that Keynes himself wasn't a Keynesian, but I think it's fair to say that Keynes never really advocated for those ideas. Keynes died in 1946 before government deficit spending outside of war or recession/depression became common place.
Why is it that liberals seem to ignore their own great thinkers or feel a need to go back in time to people like John Stewart Mill?
Conservatives have no problems promoting hacks like Friedrich Hayek and goofballs like Arthur Laffer, and Bernie Sanders type progressives don't seem to have any problems using liberals like Keynes for their own purposes.