A 27" WQHD business IPS display: specs.
Often customers report problems about humming or buzzing noises caused by badly designed power supplies when a device is connected and charged via USB-C to a display. One very bad example of this is the Lenovo ThinkVision P27h-10, but also devices from Dell and Philips seem to be noisy when USB-C charging is active. I owned one of the P27h-10 for a short time and the noise was unbearable so I returned the display to the seller. Except that the monitor was very good, sturdy built, crisp and very bright diplay. Nonetheless, I wanted to have a display where I can connect my X1 through a single cable.
The Viewsonic VG2755-2k works fine when connected via USB-C, it can provide up to 60W charging power (15W more than the Lenovo) and makes absolutely no noise. But, in order to get 2560x1440@60Hz you have to deactivate the USB 3.1 mode in the display settings, i.e. the display's USB Hub can either support USB 3.0 devices while having 60Hz refresh rate or USB 3.1 devices but then you're limited to 30Hz because of bandwidth limitations. Also, I deactivated USB-Charging because otherwise the devices connected to the display did not show up on my laptop. I think the option is badly named, since devices are still charged when this is switched off, actually the option limits those ports to be charging and not data ports (at least it looks like this). In short, the display provides WQHD@60Hz, a USB 3.0 Hub and 60W charging all over a single USB-C connection.