I think I found the Data Sheet for the Chip (ICD2042) on your Circuit Board, it's a Dual VGA Clock Generator. It supports IBM VGA, XGA and 8514 graphic applications. The Data Sheet I found is from Cypress.
You also have a Crystal Oscillator (silver can) on the Circuit Board which is used to help generate vertical and horizontal frequencies for the CRT Monitor.
The large square Chip is a Field Programmable Gate Array (FPGA). Graphic Card Companies would program this type of chip as a Graphics/Video Controller.
It looks like you have a total of 128K Bytes of Memory, which means the Video Card only has enough memory for a Monochrome Display (Black & White).
Radius made a (FPD) Full Page Display Video Card (640x864) like yours around 1991 for the Macintosh Classic. See attached Image with square Chip and four vertical Memory Chips.
Radius also made a (FPD) Full Page Display Video Card (640x864) for the Macintosh LC around 1991. I never found a picture for it.
Is there any numbers or letters on the back of your Circuit Card?