We generally recommend SDHC and SDXC memory cards with an UHS-I-interface and a SD Speed Class from 10/U1 or above, if you're using a Canon EOS 750D / Rebel T6i. More expensive UHS-II-cards do not offer any advantage in terms of speed (burst mode) or video capabilities.
Canon EOS Rebel T6i / 750D [Image source: Canon Deutschland]