To name a few...

Albert Camus

Albert Camus

Malcolm Gladwell   By Kris Krüg - http://www.flickr.com/photos/poptech2006/2967350188/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=5399298

Malcolm Gladwell

By Kris Krüg - http://www.flickr.com/photos/poptech2006/2967350188/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=5399298

Jeffrey McDaniel

Jeffrey McDaniel

V S Ramachandran   By David Shankbone - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=15057808

V S Ramachandran

By David Shankbone - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=15057808

Jiddu Krishnamurti   By Unknown - This image is available from the United States Library of Congress's Prints and Photographs division under the digital ID ggbain.38863. This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. Public Domain, https://commons.wikimedia.org/w/index.php?curid=2833431

Jiddu Krishnamurti

By Unknown - This image is available from the United States Library of Congress's Prints and Photographs division under the digital ID ggbain.38863. This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. Public Domain, https://commons.wikimedia.org/w/index.php?curid=2833431

Geralt of Rivia, The Witcher

Geralt of Rivia, The Witcher

William Shakespeare   By It may be by a painter called John Taylor who was an important member of the Painter-Stainers' Company.[1] - Official gallery link, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5442977

William Shakespeare

By It may be by a painter called John Taylor who was an important member of the Painter-Stainers' Company.[1] - Official gallery link, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5442977

Richard Feynman

Richard Feynman

Lucky Ali

Lucky Ali

Robert Burns   By Alexander Nasmyth - nationalgalleries.org, Public Domain, https://commons.wikimedia.org/w/index.php?curid=17632298

Robert Burns

By Alexander Nasmyth - nationalgalleries.org, Public Domain, https://commons.wikimedia.org/w/index.php?curid=17632298

Richard Dawkins   By David Shankbone - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=11639311

Richard Dawkins

By David Shankbone - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=11639311

Charles Dickens   By Jeremiah Gurney - Heritage Auction Gallery, Public Domain, https://commons.wikimedia.org/w/index.php?curid=8451549

Charles Dickens

By Jeremiah Gurney - Heritage Auction Gallery, Public Domain, https://commons.wikimedia.org/w/index.php?curid=8451549

Christopher and Jonathon Nolan

Christopher and Jonathon Nolan

Douglas Hofstadter

Douglas Hofstadter

Snow and Bigby, The Wolf Among Us

Snow and Bigby, The Wolf Among Us

Mikhail Tal   By Croes, Rob C. / Anefo - [1] Dutch National Archives, The Hague, Fotocollectie Algemeen Nederlands Persbureau (ANEFO), 1945-1989, Nummer toegang 2.24.01.05 Bestanddeelnummer 931-9186, CC BY-SA 3.0 nl, https://commons.wikimedia.org/w/index.php?curid=29164554

Mikhail Tal

By Croes, Rob C. / Anefo - [1] Dutch National Archives, The Hague, Fotocollectie Algemeen Nederlands Persbureau (ANEFO), 1945-1989, Nummer toegang 2.24.01.05 Bestanddeelnummer 931-9186, CC BY-SA 3.0 nl, https://commons.wikimedia.org/w/index.php?curid=29164554