Larry Niven has a few e.g. https://en.wikipedia.org/wiki/A_World_Out_of_Time but I agree that realistic interstellar travel is more often found in older fiction, as we did not yet know how hard it was. What would be realistic now?
Use of Bussard ramjets is a distinct historical phase in the numerous stories set in Niven's known space [0] universe - they are how mankind reaches and colonises the nearby stars before being given access to FTL hyperdrive by the Outsiders during the first Man-Kzin War.
[0] https://en.wikipedia.org/wiki/Known_Space