Avoid any UEFI rated card. The dell BIOS won't support it. There is no 6 pin PCIe cable so be sure your card doesn't need it. GTX750Ti has been the go to card for these. Aftermarket PSUs fit. I've used the double wide cards by cutting the bracket in 1/2 with sheet metal shears. If the cover goes all the way to the back trim it so the air can turn left.
You might install the card w/o the bracket just to be sure it's good first. Then cut it.