Since Kenyon Martin was sent back to the United States a month ago or so, his name has been linked to the Knicks a few times. Likewise, Ramon Sessions's name is inevitably linked to the Knicks at some point in the season. However, other names have been brought up in trade/signing rumors as well. Other China bros like Aaron Brooks and J.R. Smith have been mentioned, as well as Jose Calderon, who the Raptors are evidently looking to unload.
Though all of these names are potentially interesting, the problem is that the Knicks have almost nobody to trade. Outside of the "Big 3", guys like Landry Fields and Iman Shumpert are probably tradeable, but the major fluctuation in salaries on the Knicks makes it hard to trade anyone. Renaldo Balkman has the fourth highest salary on the team, and he makes below $2 million a season. This makes for a problem when it comes to matching salaries.
Sessions would be a great pickup for the Knicks, and his salary isn't too high, but the Knicks would have to combine a few players to make it work. I don't think they're interested in trading Fields or Shumpert, so it'd take some sort of combination of Balkman, Toney Douglas, Jared Jeffries, Bill Walker, Josh Harrellson, and maybe even Jerome Jordan (who I see as someone who may get interest from other teams). Whether or not any of those players are appealing to teams is another story; just their salaries would help match.
As far as free agents go, Kenyon Martin's name was linked to the Knicks in this Marc J. Spears article. However, as mentioned in that piece, Martin has other suitors that he may find more attractive. Guys like Brooks (a restricted free agent) and Smith (unrestricted) could potentially be signed for the $2.5 mil exceptiom, which the Knicks still have.
Mike D'Antoni didn't rule any trades or signings out, and said that if it "makes sense" the team will pursue it. However likely that may be though, is a different story.