Reforge materials? Are you asking how to reforge your current tools or where can you get more of the "Tool Essence" from?

Sorry for the misunderstanding, I don't believe you can get anymore in the current state. I think that those might've been added due to the the ninja tool (other than the red gourd) not having yellow stats anymore, which the gourd seems to be the only way to get yellow stats at this current time.

Hopefully a mod can answer this for us.