It seems that the charger supplied with it is a 12W 2.4A 5.2V type. So practically everything Anker ships will have this common standard. You don't need Quickcharge, nor USB-PD.
The battery inside the tablet is 27.5Wh so you're talking roughly 1.1x full recharges with the Powercore 10000. How did I calculate that? Well the Powercore 10000 is a 36Wh capacity and 37/27=1.37 but if I allow for some power losses in cable etc say 20% then 37/27*.8=1.09.
If you want a smaller powerbank then the Powercore Slim 5000 would be half a full recharge, or if you wanted more then say the Powercore II 20000 would be nearer to 2.5x recharges.
I recommend the Powercore 10000 because its enough power to get your a typical heavy day and its compact.
Do you only want to recharge the tablet from the powerbank or do you also want to charge something else? If you want to recharge other items then it is additive, you may want more USB ports on the powerbank and then also add the capacity needs. The Powercore 1000, Slim 5000 are single USB ports, the Powercore II 2000 is 3 ports, and there are plenty others with 2 ports like the Powercore 13000. If you had say an Android Quickcharge phone then consider powerbank with does Quickcharge which can then also do the common standard for the ipad.