Bought this Old late 2013 16gb a1398 15inch MacBook Pro. Had Yosemite OS installed and only 32 battery cycles. Hardly used it seems. I know people more excited about the new 2020
Amazon.com: A1502 Replacement Laptop Battery for MacBook Pro Retina 13 Inch Late 2013 Mid 2014 Early 2015; MacBook Pro A1493 A1582 Battery EMC 2678 2875 2835 ME864 ME865 : Electronics
Amazon.com: A1389 A1494 Laptop Battery Replacement for MacBook Pro 15 inch Retina A1398 (Late 2013 & Mid 2014), fit Retina ME293 ME294 MGXA2 MGXC2 MJLQ2 MJLT2 MJLU2 : Electronics
MacBook Pro 15" Retina Display Late 2013 Battery Replacement - iFixit Repair Guide
Retina, round two: Apple's 15-inch 2013 Retina MacBook Pro reviewed | Ars Technica
How to Replace the Battery in the 15-Inch Retina MacBook Pro: EveryMac.com