Here's a list of ex-Twins on active rosters at the start of the season. Rosters are as listed on each team's website as of this morning. If I missed someone, please feel free to let me know.
Baltimore: Steve Pearce, Delmon Young
Boston: Craig Breslow, David Ortiz
Yankees: Garrett Jones
Tampa Bay: Grant Balfour, Rene Rivera
Toronto: R. A. Dickey, Liam Hendriks, Steve Tolleson, Danny Valencia
White Sox: None.
Cleveland: Anthony Swarzak
Detroit: Joe Nathan
Kansas City: Kendrys Morales
Houston: Samuel Deduno, Pat Neshek
Angels: Drew Butera
Oakland: Tyler Ladendorf, Sam Fuld
Atlanta: A. J. Pierzynski
Mets: Sean Gilmartin, Michael Cuddyer
Philadelphia: Ben Revere
Washington: Wilson Ramos
Milwaukee: Matt Garza, Kyle Lohse, Carlos Gomez
Pittsburgh: Francisco Liriano, Vance Worley
St. Louis: Randy Choate
Colorado: LaTroy Hawkins, Justin Morneau
San Diego: Yangervis Solarte
San Francisco: None.