Amazon.com: HumanCentric VESA Mount Adapter for iMac 24 Inch (Aluminum), iMac 27 Inch (2009, 2010, 2011), LED Cinema Display, Thunderbolt Displays, Replaces Apple iMac VESA Adapter MD179ZM/A, iMac VESA Kit : Electronics
How do the "Mid-2011" Aluminum iMac models compare to the "Mid-2010" models that preceded them?: EveryMac.com
A1311 Apple iMac 21.5 inch 2009 2010 & 2011 Glass Panel Display Replacement | eBay
Incase anyone ever needs the answer…I have a 27” 2010 iMac working in Target Display Mode with a M1 MacBook Pro using a miniDP to USB C adaptor that's capable of 4k60Hz.
Used Apple A Grade Desktop Computer iMac 27-inch (Aluminum) 3.5GHZ Quad Core i7 (Late 2013) MF125LL/A 8 GB DDR3 1 TB HDD 2560 x 1440 Display Sierra 10.12 Includes Keyboard and Mouse - Walmart.com
iMac Intel 27" Repair - iFixit
Amazon.com: HumanCentric VESA Mount Adapter for iMac 24 Inch (Aluminum), iMac 27 Inch (2009, 2010, 2011), LED Cinema Display, Thunderbolt Displays, Replaces Apple iMac VESA Adapter MD179ZM/A, iMac VESA Kit : Electronics