A-Tech for Apple 6GB Kit (1x2GB + 1x4GB) DDR2 667MHz PC2-5300 200-pin SODIMM for MacBook (Late 2007, Early 2008, Early 2009), MacBook Pro (Mid 2007, Early 2008), iMac (Mid 2007) - Memory RAM Upgrade at Amazon.com
How to Upgrade iMac RAM (20" and 24" Aluminum): EveryMac.com
Install memory in an iMac - Apple Support
Apple iMac 21.5-inch - 8GB RAM - 1TB HDD + 128GB SSD - 2.7Ghz Intel Core i5-4570R - ME086LL/A Late 2013 (Scratch and Dent) - Walmart.com
APPLE IMAC 24 INCH (MID 2007) | eBay
Review: Apple's new 24-inch iMac (aluminum) | AppleInsider
Is it worth buying this 2007 iMac for 100$ and upgrading it? : r/mac
The infamous 2007 iMac on Catalina | MacRumors Forums
4gb 2 X 2gb Pc2-5300 667 Memory RAM for Mid 2007 Apple MacBook Pro iMac Mac Mini for sale online | eBay
Apple iMac 20” - mid 2007 - 2 Ghz Intel Core 2 Duo 4GB HD 250 GB | eBay