I’ll second Evolutionby Stephen Baxter. Shows the evolution of humanity from its lowly primate beginnings to several hundred thousand years from now, and many points in between.
Olaf Stapledon is certainly the poster child for this.
I very much like Cordwainer Smith; he posited a far future galactic society which had gone through several waves of colonization and star travel, during which the human race had changed dramatically; and during which the Underpeople were developed out of animal stock to serve him. The books are some decades old now, but strange and excellent.
Vernor Vinge does some interesting things in “A Fire upon the Deep.”
Andre Norton’s “The Last Planet” (and others) are also showing age, but think about this in interesting ways; as do her Time Trader stories. Norton, more than many writers, imagined species as things in flux; what is “human” today might be a beast in a few millenia, or vice versa.
Another approach was taken by H. Beam Piper in his future history Empire; he tended to assume that on any scale short of millions of years, humans would probably remain the chaotic batch we know.
C. J. Cherryh just touches in this in “Cyteen”, where she raises the issue of galactic colonizations dividing humans into differentiated subspecies; some of which might prey upon others.
Lois McMaster Bujold, in her Vorkosigan stories, has several books which involve the Cetagandans - a society quite intentionally breeding for a post-human race.