Here's a few leftover vouchers from the Holiday giveaways:

THUO-2AD-11OS-ALDG-VT77
PX8-7VD0-6VFA-GHLL-U10Z
8HEO-JF6I-48IB-3R0A-EMY0
BOFV-RR8R-0HLY-ZDWD-OEHL

There's still some remaining, and they will be dropped occasionally in chat, so check in on New Years Eve and New Years Day if you want to grab some.