Fil-Tec Pre-Wound Bobbins are the industry leader.

Red Rock Threads carries the following Lines and Sizes of Mettler Thread:

Fil-Tec Magna Glide 60wt Poly Pre-Wound Bobbins
Made of high-tenacity polyester thread. The patented magnetic core creates consistent delivery throughout the entire bobbin.
  Fil-Tec Magna Glide 60wt Poly Pre-Wound Bobbins

Fil-Tec Clear-Glide 60wt Poly Pre-Wound Bobbins
Available in bulk boxes and clear plastic tubes. High grade polyester thread.
  Fil-Tec Clear-Glide 60wt Poly Pre-Wound Bobbins

Fil-Tec Magna-Glide Delights 40wt Polyester Pre-Wound Bobbins
Consistent tension throughout the bobbin increases stitches per bobbin. This equates to more time quilting and fewer bobbin changes.
  Fil-Tec Magna-Glide Delights 40wt Polyester Pre-Wound Bobbins

Fil-Tec Clear-Quilt 50wt Cotton Pre-Wound Bobbins
Available in bulk boxes and in tubes. 50wt Egyptian cotton.
  Fil-Tec Clear-Quilt 50wt Cotton Pre-Wound Bobbins

Fil-Tec Magna-Quilt 50wt Cotton Pre-Wound Bobbins
Has the look of cotton but has the strength and colorfastness of polyester.
  Fil-Tec Magna-Quilt 50wt Cotton Pre-Wound Bobbins