  We continue our program of publishing all planets (and possible planets)
found by eye in 2021 Korea Microlensing Telescope Network (KMTNet) online data.
We present 4 planets, (KMT-2021-BLG-0712Lb, KMT-2021-BLG-0909Lb,
KMT-2021-BLG-2478Lb, and KMT-2021-BLG-1105Lb), with planet-host mass ratios in
the range -3.3 < log q < -2.2. This brings the total of secure, by-eye, 2021
KMTNet planets to 16, including 8 in this series. The by-eye sample is an
important check of the completeness of semi-automated detections, which are the
basis for statistical analyses. One of the planets, KMT-2021-BLG-1105Lb, is
blended with a relatively bright $(I,V)\sim (18.9,21.6)$ star that may be the
host. This could be verified immediately by high-resolution imaging. If so, the
host is an early G dwarf, and the planet could be characterized by
radial-velocity observations on 30m class telescopes.
