1) What yarn (that you don’t have/haven’t used) would make your stash “complete”?
Quiviut - it is the softest yarn I have ever touched. I have been dreaming about it ever since I was allowed to touch it at Ally Pally last year.
However, on a more affordable level, but still hard to get, a skein of Poshyarn would make me happy at present, too. ;-)
2) What yarn do you never want to be without?
Sockyarn - especially:
Wollmeise 100 % Merino superwash sockyarn.
But Socks that Rock was wonderful to knit with, too.