Simple. *This applies for charging on the Switch ONLY*
If you're using standard size USB-A, it tops out at 5V1.5A-2A.
If you're using USB-C, you can improve the charge rate if it has USB-PD capability that allows current draw of 5V, 9V, 15V and 20V, with varying amperage up to 5A.
The Switch only takes up to 2.6A, its own official AC charger tops out at 15V 2.6A.
Standard USB-A cant do 15V, only USB-C does, and ONLY if it has USB-PD capability.
Any form of quick-charging/fast charging isn't supported other than USB-PD. Check your AC charger or powerbank. If it advertises more than 2A out of its USB-A, it's a form of quick-charging. It wont work on the Switch though, charging on USB-A will top out at 5V 1.5A-2A on the Switch.
USB-C is a bit more complex. I'll stop here unless you want to delve into the complicated mess that is USB-C PD.
I recommend these:
Wall Chargers: Anker PowerPort+ 5 with USB-PD (Model A2053111).
Powerbanks: RAVPower 20,100 mAh Powerbank with USB-PD (Model RP-PB059), RAVPower 26,800 mAh Powerbank with USB-PD (Model RP-PB058-2), Xiaomi ZMI QB820 20,000mAh Powerbank with USB-PD.
Cables: Apple USB-C 2M cable [Model MLL82AM/A (A1739)], Belkin USB-C 2M cable [Model F2CU030bt1M-BLK].