Each of the three players spent time in the American Hockey League last season.
"These players add significant depth to our organization," said Dave Poulin, vice president of hockey operations, in a press release. "They all have experience at the NHL level and will provide strong leadership for our young prospects."
Zigomanis is a veteran of 189 NHL games, and split his time last season between the Toronto Marlies (AHL) and Djurgardens of the Swedish Elite League. The 29-year old has spent time in the NHL with Carolina, St. Louis, Phoenix, and Pittsburgh.
Crabb, 27, had 24 goals and 29 assists with the Chicago Wolves (AHL) last year. He has played 29 NHL games with the Atlanta Thrashers.
Richmond split his time in 2009-10 in the AHL with Peoria and Rockford. The 25-year old has 49 games of NHL experience with Carolina and Chicago.