Here's a list of the undergraduate schools attended by the residents at various prestigious institutions.
Johns Hopkins neurosurgery:
Yale, University of Florida, University of Illinois, Instituto Tecnologico y de Estudios Superiores de Monterrey, Campus Saltillo, Yale, NYU, Wake Forest, Stanford, Miami University of Ohio, Barnard, UT Austin, University of Utah, Johns Hopkins (2), CUNY Queens, University of Athens School of Health Sciences, Harvard (2), UNC Chapel Hill, INS Serrallarga, Brown
http://www.hopkinsmedicine.org/neurology_neurosurgery/education/residencies/neurosurgery_residency/current_residents/
Stanford OBGYN:
Penn, Texas A &M, Georgetown, U of Southern California (2), Duke, Stanford (2), Yale (2), Williams, University of New Mexico, UC-Berkeley (2), University of Illinois at Chicago, Queens University, Cornell, Johns Hopkins, UCLA
http://obgyn.stanford.edu/education/residency/roster.html
Stanford Emergency Medicine:
Franklin and Marshall, UC-Berkeley (2), Southern Illinois University-Edwardsville, Brigham Young University, Harvard, Adelphi University, University of Vermont, University of Southern California, Whitman College, UT-Austin, Temple, Notre Dame (2), UC-Davis (2), La Sierra University, Princeton (3), University of Utah, Stanford, Williams, UCLA (3), Harvey Mudd, NYU, UVA (2)QQ, San Francisco State, Millsaps College, Oklahoma State, Air Force Academy, Smith, Michigan State, UC-Santa Barbara, University of Toronto, Boston University, Dartmouth, University of New Mexico, University of Nevada Reno, University of Washington
http://obgyn.stanford.edu/education/residency/roster.html
Stanford Ophthalmology:
Duke, Northwestern, UC-Berkeley (2), Penn, MIT (2), Vanderbilt, Harvard, Boston University
http://ophthalmology.stanford.edu/education/residency_current.html
NYU OBGYN:
Cornell, Wesleyan, Boston University (2), Brown, NYU (3), Wake Forest, Tokyo Institute of Technology, Wake Forest, UMass, Yale (2), University of Washington, Tufts, Columbia (2), Queen's University, Georgetown, University of Michigan
https://med.nyu.edu/obgyn/educational-programs/residency-program/meet-our-current-residents
Penn Orthopaedics:
Penn (4), University of Richmond, UCLA, UC-Santa Barbara, Notre Dame (2), University of South Carolina, University of Delaware, Harvard (2), UConn, University of Missouri-Kansas, Boston College (2), UMass, Brigham Young, Cornell, Northwestern (4), Rice, Duke, University of Rochester, University of Wisconsin, Bryn Mawr, William and Mary, Providence College, Michigan State, University of Southern California, Rutgers, Emory, Creighton, Colgate, The College of New Jersey, Pitzer, University of Leicester, North Carolina State
https://www.pennmedicine.org/departments-and-centers/orthopaedic-surgery/education-and-training/residency/current-residents
Yale orthopaedics:
Hamilton, Columbia, Air Force Academy, Yale, Colorado State, Duke, Cornell (2), University of Massachusetts Boston, Brigham Young, Princeton (2), University of New Mexico, Ohio State, SUNY Albany, JMU, Emory, Illinois Institute of Technology, Barnard College, Wheaton College of Illinois
https://medicine.yale.edu/ortho/education/residents.aspx#page4
Duke General Surgery:
Duke (3), Yale, Columbia, Pomona, University of Michigan, John Carroll University, University of Kansas, Rice, Florida Atlantic University, Johns Hopkins (2) , University of Washington, Georgetown, University of Chicago, Boston College, Stanford (3), Emory, Vanderbilt, Penn State, Butler, WUSTL, University of Wisconsin (2), MIT, Kalamazoo College, Clemson, Carnegie Mellon, Harvard, UNC-Chapel Hill, Union College, Omdurman Islamic University, UVA, Haverford, Rollins College, Indiana University,
https://neurosurgery.duke.edu/education-and-training/neurosurgery-residency/current-residents
Yale Neurosurgery:
University of Michigan, Biola University, Johns Hopkins (3), Cornell, University of British Columbia, University of Bridgeport, WUSTL, UC-Berkeley, Harvard (2)
https://medicine.yale.edu/neurosurgery/education/residents.aspx
Yale Plastic Surgery:
NYU (2), University of Georgia, Johns Hopkins, University of Mississippi, Bates, Harvard, Denison, RPI, Case Western, University of MIchigan, Queens University
https://medicine.yale.edu/surgery/plastics/education/residents.aspx#page8