Hello,
Every item you can only craft/buy for event materials/tokens you can get after the events.
Like on Winterfest, Black Kat event, Tortodrone, Black Kat (Sprite) and some more.
Once there was a very good and helpful update.
In this update a Mysterious Alchemy Machine and Token traders like Montague got added.
Now you can meet these in Haven or in Moorcroft Manor (Arcade depth 8) and you can use the event items everytime.
It would be really great if you would add the Sould-trader from Apocrea Mission as well. (i don't know the name of the trader)
Then we would be able to use our Tokens to get some more materials to craft Obsidian weapons or to get a Grasping Aura.
Greets
I 100% agree with OP and this needs to be in the game because I forgot to trade in my other 1470 sigils for the last materials I needed. I mean, who wants to wait half a year just to trade tokens? Nuff said.