I've got a Ravpower 20100mAh powerbank here that's surplus to requirements. I purchased this brand new while in the US over Xmas and it was an impulse buy without really considering whether I needed it or not.
While it's an amazing device I've got other powerbanks and have done nothing except charge it and never used it so I've decided I don't really need it.
Those who know me will know I love Anker and Ravpower and think they're the two best brands of chargers on the market. This device supports QC3.0 + USB-C and can be charged via USB-C or micro USB QC3.0 which means it will charge quickly. This is not the PD model (that's quite a bit more expensive) so if you need USB-C PD support you won't want this model.
These currently sell for US$49 + tax on Amazon and the price has dropped since I purchased it so I'll be happy with NZ$65 for it. You won't be able to buy anything locally that even comes slightly close to this quality wise for this price.
Obviously shipping lithium powerbanks is no longer permitted by NZ Post or Courierpost so I can't post this unless somebody wants to arrange their own courier for pickup and pay for it and take responsibility for the package. With this in mind I'd prefer a Wellington customer or somebody in Auckland (I'll next be up there in the CBD on the 20th/21st so could drop off).