powerbank (fast charging)

Spigen, Samsung -> good quality cells

Duracell & portronics -> I've never used, but their reviews are good, however, battery quality I expect same as ambrane etc.

Mi and samsung are only good.

Any others can die unexpectedly.

Mi power bank been using for two years

Mi - So far bought 3 power banks from Mi. All are 20000 mAh. Oldest is bought 7 years ago and still in good condition. Other two are relatively new.

I have seen people in my extended family using other known brands and they did not last long. 

I bought a 10000 mah Samsung power bank back in 2014 and it is still working extremely well now, though I've used it very rarely like 4-5 times in a year. But I'm still happy with its charge retention effectiveness.