Speaking of small impact on many people's lives, I absolutely love to read biographies/profiles of people and companies. Some of my favorites include: Abe Lincoln, Ben Franklin, Elon Musk, Steve Jobs, Aldo Leopold, Jerry Garcia, Einstein, Alan Turing, Ted Turner, Brian Cranston, Bob Dylan, Willie Nelson, Bernie Sanders, Richard Branson, and so many more...
And then there's people like Jesus, Marcus Aurelius, Marx, and the Budda. Who seem to have made an impact on another order of magnitude.
(Not joking about Jesus... I'm not necessarily religious but Jesus was a radical dude who lived a radical life and spoke radical messages. Pretty cool when you think about it in a historical context. There are some valuable lessons to be learned from him.)
Even after knowing and reading about the stories of many great people who have lead unique and innovative lives. I still am blown away by the life of Marcus Aurelius. His life was a rare intersection of power, compassion, philosophy, and understanding. Reading Meditations was a major inflection point in my life. I try to emulate his example in some ways.
Claude Shannon
As important, or more important, than Alan Turing.
we owe digital electronics to him!!
John McCarthy
Invented (or perhaps "discovered") Lisp
Seymour Papert
invented LOGO and thus
brought Lisp to little kids
Alan Kay
invented Smalltalk-72 to bring OOP
to little kids.
Ivan Sutherland
Computer graphics pioneer
Douglas Engelbart
mouse, hypertext, GUI... see "the mother
of all demos." Hugely influential.
and... Everybody at Xerox PARC in the 70s and 80s.