Brandon Moss and Kelly Shoppach are the two names being bandied about, but I don't know that either makes a lot of sense for Texas in a straight up swap. Moss is at least a year or two away from being ready for the majors, after posting a 778 OPS last season at AA (albeit at a young age, 22), while Kelly Shoppach is a solid catching prospect, but basically duplicative of what the Rangers already have in Gerald Laird.
And, as has been mentioned, Carlos Delgado is supposedly on his way to the Mets for Mike Jacobs and Yusmeiro Petit. That's roughly the equivalent of the Rangers trading, say, John Danks and Will Smith (if Will Smith could catch a little) for Delgado. More than the Rangers wanted to give up, no doubt.