I think they've changed a bit both years that they've been out (at least I think it was only 2 years) but you get them from quests usually(I think the first year it was only Major Drills and the second year it was all quests? Or something). It starts on New Year's Day and I believe runs for about a week, there will be a news post about it when they become available
From what I could find, they were given out through all the quests for both years.
But yes, I expect there will be an announcement when they are available again, and another one before they get pulled until next year.
Okay, then nevermind xD Drills must have had a different exclusive somewhere along the way OTL
I vaguely remember something about Drills as well, but I have no clue what. A chance to receive some retired New Year items perhaps? I'm really not sure though.
I feel like they were goodie bags instead. Blue ones of some sort, maybe that was new years? Or an anniversary and I'm just really misremembering (also a possibility :P )?
Hmm, that does ring some bells now that you mention it. But yeah, I'm not sure either which event it was really for. :P
Oh well, I guess we'll see what they end up doing this year! Although I don't see why they wouldn't do the New Year Tokens again at least.