Best Buy: Dell 28" LED 4K UHD Monitor Black S2817Q
Amazon.com: HP V28 4K Monitor - Computer Monitor with 28-inch Diagonal Display, 3840 x 2160 at 60 Hz, and 1ms Response Time - AMD Freesync Technology - Dual HDMI and DisplayPort -
MP 28 Inch 4K UHD Monitor | 4K Gaming Monitor | Mobile Pixels
Lenovo L28u-30 Monitor 4K Ultra HD LED 28" - Pixmart®
Philips 288E2A 28" IPS 4K Ultra HD 3840 x 2160 FreeSync Monitor – DynaQuest PC
28 Inch Monitors for All Applications | Overclockers UK