Claw of Chaos

The next event is the Christmas event re-run and neither the shop nor lotto has any. Cant say I know about the drop rates for them if any of the quests drop them often enough to farm it. https://fategrandorder.fandom.com/wiki/Christmas_2017_Event_(US)

Same deal with the following 2018 Christmas event. https://fategrandorder.fandom.com/wiki/Christmas_2016_Event

Don't know about events,but now in the ice zone expert has a Chimera with a good drop rate for Claws

Why dont you farm at snowfield ? 21% drop + ce bonus rate up = easy farm