Mra
Yea, don't get me wrong. I'm not promoting Martinaire (MRA) as being the best place to work in the DFW area. I'm simply putting out a suggestion if you would like to work in and around the DFW area.
Ameriflight (AMF) is considered a higher caliber cargo operation when compared to MRA, but getting a Dallas base is very difficult because DFW is one of AMFs most senior bases. AMF flies about 4 Emb-120s and 2 or 3 metros and 2 Pa-31s out of DFW and most of those guys are high on the seniority list.
Other DFW operators are Telesis, GTA, and Airnet (Lear jets only, I believe). There's really not much here as far as FAR 135 cargo goes. The rest of the flying here is mostly Corporate, Air Ambulance, Fractional, or Regional (American Eagle).
Even if you get on with MRA it doesn't mean you'll get Dallas as a base right off the bat. There's a 50/50 chance you'll get sent to one of their other far away bases first and as soon as people leave for better jobs DFW will come available for you. MRA is not a great place to work at, but simply a place to hang out until something better comes along.
Good Luck!