Abstract We continue our program of publishing all planets (and possible planets) found by eye in 2021 Korea Microlensing Telescope Network (KMTNet) online data. present four (KMT-2021-BLG-0712Lb, KMT-2021-BLG-0909Lb, KMT-2021-BLG-2478Lb, and KMT-2021-BLG-1105Lb), with planet-to-host mass ratios the range <mml:math xmlns:mml="http://www.w3.org...