Joshua Neustein

http://www.joshuaneustein.com

Luis Manuel Serrano’s collages

He is a mexican friend.
His work is inspired by Joseph Cornell (1903-72, American sculptor, one of the pioneers and most celebrated exponents of assemblage). 
http://lmserranodiaz.blogspot.com/

Kurt Schwitters’s collages

German Dadaist Painter and Sculptor, 1887-1948
http://jwatrous.org/art18/ks-collages-web/
http://www.guggenheimcollection.org/site/artist_work_lg_144_5.html

Maraak, Variation I (Merzbild),  1930. Oil, rusted steel, laminate, enameled tin butterfly, paper, cork, and china, mounted on board, 18 1/8 x 14 9/16 inches. Peggy Guggenheim Collection. 76.2553.87. Kurt Schwitters © 2007 Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn.

Issac Tobin’s collages

Wow!!!
http://www.isaactobin.com/index.php?/projects/potpourri/