MacBook Pro 15", Mid-2012 - i7 2.6GHz - 16GB RAM - 4TB SSD - Blu-Ray - AC Wi-Fi | eBay
A-Tech 16GB Kit (2x8GB) RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
LOGIC BOARD For 15" MacBook Pro Retina A1398 Mid 2012
16GB 8GB 4GB DDR3 1600MHz RAM for Apple MacBook Pro Mid 2012 sodimm Memory lot | eBay
Apple MacBook Pro 13” Catalina 1TB SSHD 16GB RAM 2.5GHz i5 Non-Retina macOS 2012 | eBay
Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3L 1600MHz for Mac Book Pro( Early/Late 2011,Mid 2012), iMac(Mid 2011,Late 2012,Early/Late 2013,Late 2014,Mid 2015), Mac Mini(Mid 2011,Late 2012) MAC RAM at Amazon.com
Update: Finally got 16GB RAM for my 2012 Macbook Pro 13". Hoping that I'll be transitioning to an M1 Macbook soon. : r/macbook