Just a quick FYI for UE4/UT4 mappers... textures.com has some good quality textures in the PBR section. All materials are in the metallic/roughness format and in general look pretty good in UT4/UE4 without any tweaking through materials nodes. You can download up to 15 1024x1024 textures per day for free and there are no watermarks on the free versions either!
Higher resolution versions of the textures are only available with paid credits. I'd probably buy higher res versions of several textures if the payment scale wasn't so heavily weighted against small purchases. It costs a lot more per texture to purchase a small number of credits for immediate use than a larger pack and even less for monthly credits (credits are monthly, payment for them is all up front).