Not sure if thats what you are asking but there are some items that grant additional strength damage bonus like candlewake/shroud royal/lazhruk's round shot mo, etc. You can search for them in documentation.
Found first SSSU, worth building around for faultz? My current barb kinda sucks at farming it. I was thinking about going shurikensin but i've never played sin before. https://imgur.com/a/OLO6nEY
Plague seems... Useless? Been farming k3k for a while and doing some 120 charms inbetween, poison damage from plague is not even enough to finish half hp skellies without totem buffs. Proc from Scales of the serpent does more damage than this thing even.