The Eizo Foris FS2735 is a feature-packed 27" 1440p gaming monitor that comes with a refresh rate of 144 Hz and FreeSync support. Its price tag is hefty, but it performs well enough to be used by eSports professionals, both in terms of in-game responsiveness and picture quality.
The AOC AGON AG271QG is one of the least expensive 27" high-end gaming monitors on the market. Your money will buy you an AHVA (IPS-type) 1440p panel with a refresh rate that goes all the way up to 165 Hz, as well as a G-Sync module for sublime smoothness of in-game action.
The Acer Predator XB271HU is an impressive gaming monitor equipped with a 27" 1440p IPS panel that can be overclocked from its native 144 Hz to 165 Hz. Absolute smoothness of in-game action is ensured by the built-in G-Sync module, and its ultra-thin screen bezels make it as immersive as they are downright pretty to look at.