  Earth-sized planets in the habitable zones of M dwarfs are good candidates
for the study of habitability and detection of biosignatures. To search for
these planets, we analyze all available radial velocity data and apply four
signal detection criteria to select the optimal candidates. We find ten strong
candidates satisfying these criteria and three weak candidates showing
inconsistency over time due to data samplings. We also confirm three previous
planet candidates and improve their orbital solutions through combined analyses
of updated data sets. Among the strong planet candidates, HIP 38594 b is a
temperate super-Earth with a mass of $8.2 \pm 1.7$ $M_\oplus$ and an orbital
period of $60.7\pm0.1$ days, orbiting around an early-type M dwarf. Early-type
M dwarfs are less active and thus are better hosts for habitable planets than
mid-type and late-type M dwarfs. Moreover, we report the detection of five
two-planet systems, including two systems made up of a warm or cold Neptune and
a cold Jupiter, consistent with a positive correlation between these two types
of planets. We also detect three temperate Neptunes, four cold Neptunes, and
four cold Jupiters, contributing to a rarely explored planet population. Due to
their proximity to the Sun, these planets on wide orbits are appropriate
targets for direct imaging by future facilities such as HabEx and ELT.
