Baseball America has a handy little post with all 30 Major League teams' minor-league free agents. For our purposes, here are the Astros' minor-league free agents (with statistical context provided to you, free of charge, by Astros County):
Luis Alvarez
Alvarez has spent his entire career with the Astros, debuting as a 17-year old in the Venezuelan Summer League. The catcher played at four different levels in 2013 (Tri-City, Quad Cities, Lancaster, and Corpus), hitting .282/.340/.511 in 41 games.
Michael Burgess
Burgess spent 2007-2010 with the Nationals' organization before sliding over to the Cubs for 2011-2012. He landed with Corpus in 2013, where he hit .203/.278/.378 with 12HR in 98 games.
Cody Clark
Cody Clark - perhaps the most heart-warming story of 2013 - is a minor-league free agent. When Castro went down with the knee cyst and Max Stassi got plunked in the coconut, Clark - who had been in the minors since 2003 (645 games/2337 PAs) got called up. He didn't hit all that well, but he threw out seven of 13 base runners.
Sergio Escalona
Escalona threw in 49 games for the 2011 Astros, posting a 2.93 ERA/1.27 WHIP in 27.2IP as a LOOGY. He missed all of 2012 due to injury, and only threw 15IP in 2013 for Corpus, where he posted a 6.60 ERA/2.07 WHIP.
Murilo Gouvea
Gouvea came to the Astros from the White Sox in 2009, and did not pitch in 2013. For Lexington, in 2012, Gouvea was 2-7 with a 3.71 ERA/1.17 WHIP, with 87K:29BB in 77.2IP.
Cameron Lamb
24-year old Australian reliever Cameron Lamb threw for three Astros affiliated in 2013 for a total of 58.2IP, with a 4.60 ERA/1.52 WHIP with 40K:23BB. Oddly, his best stretch was 19 games for Lancaster, where he had a season-best 3.95 ERA/1.35 WHIP.
Che-Hsuan Lin
Lin came over to the Astros last off-season after spending his career in the Red Sox organization. He got three hits for the Red Sox in 2012 (two in his 2012 season finale against the Yankees). For OKC in 2013, Lin hit .234/.356/.309 with an impressive 56K:60BB. He's a career .253/.349/.339 hitter in the minors.
Jose Martinez
Martinez, an infielder who spent most of his time in 2013 at 2B, played in 81 games for OKC hitting .282/.316/.410. He's a career .278/.326/.408 hitter between the Cardinals and Astros organizations. The Batguy wrote a nice thing about him in April 2012.
Carlos Quevedo
Quevedo has spent his entire career with the Astros' organization. In 2013, he threw 85IP between Lancaster and Corpus - but 81.2IP of those came at Double-A, where he allowed a 3.53 ERA/1.21 WHIP, with 59K:20BB and 14HR. He has a career walk rate of 1.5 BB/9 and a 4.64 K:BB ratio.
Former Astros on the list include:
Edwin Maysonet (CHC), Brian Bixler (NYM), Fernando Martinez (NYY), Travis Buck (SD), Jason Jaramillo (SEA), Travis Blackley (TEX), Jimmy VanOstrand (WSH) and Jason Michaels (WSH).