First off I would like to say much appreciation is due to David Thomas for the past few years. I was excited to have a high character guy come come over from New England via trade. Thomas turned out to be worth every penny, as he was clutch at big times, worked hard, and never complained about being the second guy in line.
Now that he is gone here some of the better options to replace him:
Michael Higgins--New Orleans Saints Image: http://www2.pictures.zimbio.com/gi/Mike+Higgins+Jacksonville+Jaguars+v+New+Orleans+SrAFRTjHqnOl.jpg
His frame and build allow him to be a better blocking TE than a recieving TE. However, don't let that special teams classification fool you, Higgins shows his skills of running routes and more than capable hands that could allow him to fit nicely in the back up role that Thomas filled. He is a better blocker than Thomas was, but the the only thing that worries some with Higgins is his pass catching abilities over the middle. The Saints use Jimmy Graham for their down the seam TE routes, but David Thomas was known to have his nifty catches down the middle as well. It would not surprise me for Higgins to make the final roster out of camp and be a contributor going forward. Higgins has been on the practice squad sicne the end of the post season in 2011. He spent the last six games of the 2011 season on the active roster and throught the post season. He is currently one of two TE's on the Saints' roster according to their unofficial depth chart.
Brandon Myers--Oak Raiders--UFA Image: http://cbssports.com/images/blogs/wip-9-oak.jpg
Myers debuted for the Raiders in 2009 after being selected with the 202th pick in the 6th round. He has been their safety net since then and is a solid blocker with good pass catching abilities. He seems to never be taken down by one tackler and is an enthusiastic and compassionate player. He is praised for his locker room character and hard work. Myers had his best season as a pro in 2012 pulling in 75 REC 753 YDS and 4 TD's. The numbers make him seem like a average to big money guy as an UFA, but he only made 565K last season. The Saints could potentially offer him somwhere around 2-3 years at $2-3 mil.
Hayden Smith-- New York Jets Practice Squad Image: http://rantsports.media.s3.amazonaws.com/nfl/files/2012/10/Hayden-Smith-New-York-Jets.jpeg
Hayden Smith brings his tough mentality and work ethic from the Australian Rugby league to the NFL. Smith is exciting to watch in anything that he does and brings it on every play wether he is blocking or running routes. It is rumored that in training camp last season, Smith would get under the skin of the Jets' first team offense multiple times a day. Jets officials are quoted as saying "We just couldnt cover the guy and it would drive Rex crazy on a daily basis". Witht he right offensive coaches, scheme, and QB throwing to him, Smith could turn into a quality backup. Smith is currently under contract for the 2013 and 2014 season but will most likely be put back onto the practice squad.
Another option is to go after a TE in the draft which I don't see the Saints doing until possibly the 4th or lower round. The draft is not stacked with TE's this year after the first couple of guys.
Feel free to add any as these three guys are the only ones I've found so far...I will add some more as I search today.