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

I know how to do it, I'm asking from where I can get them?

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.

Okay;thank you for sharing with me what you know

That's correct.

As of right now, there's no way to farm Tool Essence shards.
However, There are TI items that do provide gold stats.

I'll suggest saving the essence for when the time is right, use them to reforge proper stats onto your item.

so it's better to save the Tool Essence untill we get red ninja tools?

It's optional.

You may either use them on the better items or save them.
I would personally recommend saving til your tools are fully upgraded.

Ok! thank you very much! :)

Not a problem.

Not a problem.