I know your PCIe x16 slot is used so you have one PCI and 2 X1 slots left.
I guess you are asking for a PCI or X1 video card. Newegg has them.
https://www.newegg.com/Product/ProductList.aspx?N=100007709%20600007854&IsNodeId=1&Submit=ENE
Go with the 41 buck 710 card.

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