You can use any PCIe x16 based video card. And most gaming cards are dual slot. What you can't do is put 2 of the same cards and combine them to give you a increase in FPS during games. You can install 2 video cards and set it up to run multiple monitors.
The board you pick only has 1x PCIe x16 and you can only install one video card.
If you want to install more than 1 video card, you need a board with 2x PCIe x16 slot.