I was going to say any of them other than the Pirates, but I guess that's over with.
The only logical choice WAS the Pirates.
Stronach already has enough signatures and had no trouble collecting them.
BZÖ and CPÖ ? No way. (BZÖ will collect enough signatures anyway).
KPÖ is only running in Salzburg and suburbs, so I cannot sign it, because I don't live there.
NEOS has not yet decided if they run and the deadline is fast approaching. So I cannot sign their petition either, because they don't have it on their site yet.