I am currently using STM32F429I DISCOVERY kit for my project, I intend to use 7 inch fsmc touch screen display compatible with the kit, it would be a huge help if anyone can suggest a suitable display.

[Tesla DeLorean]

Kind of put the cart before the horse there.

Perhaps the more considered approach would have been to pick a board where the LCD is removable/replaceable at least.

If you are committed to the F4 series there are perhaps eBay boards, or some of ST's EVAL series. The F469 can drive DSI displays, the RPi 7" display might be workable with leet skillz. The F769I-DISCO does have a connectorized display.

GHI Electronics has some board/screen options

https://www.ghielectronics.com/products/ucm

https://www.ghielectronics.com/products/ucm/uc2550

https://www.ghielectronics.com/products/ucm/dev-options