Amazon.com : D-LI109 Battery Charger for Pentax K-R, K-S1, K-S2, K-30, K-50, K-70, K-500 Digital SLR Digital Camera : Electronics
Power Bank USB Cable+D-LI109 Dummy Battery D-DC128 DC Coupler+Quick Charger for Pentax K-70 K-50 K-30 K-R K-2 K-S1 K-S2 Camera - AliExpress
Amazon.com: Pentax K-50 Digital Camera Battery Charger (110/220v with Car & EU adapters) - Replacement Charger for Pentax Dli-109 Battery - : Electronics
Amazon.com : Glorich K-AC128 D-AC128 K-AC109 K-AC168 D-DC128 Replacement AC Power Adapter Kit for Pentax K30 K50 K70 K-r K2 K-S1 and K-S2 Digital SLR Cameras,D-Li109 Replacement(but not Compatible with Pentax KP) :
Amazon.com : BM Premium 2 Pack of D-LI109 Batteries and USB Dual Battery Charger for Pentax KP, K-R, K-S1, K-S2, K-30, K-50, K-70, K-500 Digital SLR Camera : Electronics
HQRP AA Battery Holder-Adapter for Pentax D-BH109 K-r K-30 K-50 K-500
Battery wrongly stuck in Pentax K-50 - PentaxForums.com