Ok so I am stumped with tailoring.
Leather, blood, and bone chips can be used in Tailoring. However, in the discovery section the game will not allow me to use them. I can only use them with known recipes for some odd reason.
If you've discovered everything, then you can't use them in discovery anymore. The only things you can discover with bone chips and blood are insignias.
If you want to cheat, http://www.gw2db.com/recipes/tailor?sort=requiredrating