MicroQuilter by Superior has been getting rave reviews for its strength, ease of use, and results. This thread is quickly becoming quilters go to thread for machine applique, detail quilting, and micro quilting. It works great for both machine quilting and long arm.
Here is the description and video from Superior:
MicroQuilter is a 100 wt. 2-ply extra-fine polyester thread designed for invisible machine applique, detail quilting, and stitch in the ditch. It is an extremely fine thread that can be sewn with a very small needle, rendering the thread virtually invisible. MicroQuilter is noticeably strong, especially considering its thin diameter and is the preferred thread for micro stippling and miniatures. MicroQuilter can be used on home machines and longarm machines and is available in 30 colors on 3,000 yd. cones.