Presuming your mobo has at least 2x PCIE x16 slots... you can use 2x, 4-port Nvidia cards to run up to 8 monitors, no worries... like NVS 510, Quadro P600/P620/P1000/P2000. All are excellent. (Later/newer ones are faster and with more VRAM, of course.)
All of which will run UHD resolution...