Sub suggestions

I have Tyler Taylo Mini Ref speakers with a NAD 320bee int. amp. The speakers are front ported. The room is 10x13 I would like a sub of modest expense that would pair up nicely. Any suggestions?

There is a review that looks interesting at Enjoy the Music of the Tekton subwoofer ($650), but I have not heard it myself. I have heard an Outlaw sub and thought it was pretty good. I would insist on a home-trial before committing, since you never know how well a sub will blend with your mains and work in your room.
SVS SB12-Plus is my suggestion. Sealed, builtin bass management, analog PEQ, small footprint. I use it in my office system with KRK active monitors. It'll work great with your setup thanks to your NAD integrated amp. Wire it between the preamp and amp section of the NAD and the sub will handle the bass load.
Omega Cube or Deephemp Sub. Perfect for music in a small room.