Crucible Steel Knife
I covered making this crucible steel knife last year:

My usual setup consists of low-phosphorous wrought iron, charcoal powder and a Vanadium contributing tool steel such as O1. However, It may be time to engage in more crucible steel experiments.

Commenters on Youtube suggested to make Game of Throne themed Valyrian steel which supposedly was made with Dragonglass aka Obsidian. As Obsidian consists to a large percentage of aluminum oxide with a melting point >3700F that does not seem very feasible.

Another option would be to use meteorite, e.g. Campo de Ciello, which has high nickel content.

Any other ideas for the next crucible run?