For me, a quiet shot is about tuning and silencer placement. I can't tell a difference between skinny or not, all else being equal.
HMPE (already defined) is the base material for all "Fast Flight" type string materials. Original FF was SK65. Dynaflight '97 is SK75. Dynaflight 10/Force 10 is SK78. 8190 is SK90--the strongest, most durable HMPE string on the market to date.
Materials like 450+ and 452X add Vectran to further reduce stretch and creep. Trophy has Vectran and GORE fiber.
I only use BCY products because they only use the best of the best of HMPE fibers--brand name Dyneema. 8190 is the ONLY string material with SK90 in it to date--BCY has exclusive rights. There are cheaper imitations in some other materials.
Polyester materials (B-55, B-500, B-50) will do the job, but they won't do anything the HMPE materials can't do--except stretch and creep more, and wear faster.