The AMANN GroupAmong the most commonly use Amann product is their
Rasant range of thread but they also make a wide variety of thread types from embroidery to industrial thread.
From their web site you should be able to set your preferred language and find out where to buy their products in your own country.
http://www.amann.com/enCoats GroupCoats are an old English company that have been making thread since 1755 and are the largest thread manufacturer in the world.
Well known products are Coats
Astra that is used in both sewing machines and overlockers. They also make
GRAMAX which is a specialised overlocker looper thread for fine garments and stretchwear.
http://www.coatsindustrial.com/enTHREADS (India) LimitedPart of the LOHAI GROUP
A manufacturer of a wide range of thread types for clothing and industrial tasks.
http://www.threadsindia.com/GütermannA German manufacturer of many high quality and specialised thread types.
https://www.guetermann.com/