Any chandlery will have suitable rope.

Double braid polyester is a fair choice for general use. Not much stretch.

Breaking load double braid polyester:
6mm 1000kg
8mm 1600kg
10mm 1900kg
(Note breaking strength is not safe working load - if potential for person under the load, you should work to a wide safety factor, say 5x, e.g. SWL 200kg for 6mm rope)

(Also note that I am an uneducated mug with no relevant expertise and everything I just said could be entirely wrong)