  The search for habitable planets has revealed many planets that can vary
greatly from an Earth analog environment. These include highly eccentric
orbits, giant planets, different bulk densities, relatively active stars, and
evolved stars. This work catalogs all planets found to reside in the HZ and
provides HZ boundaries, orbit characterization, and the potential for
spectroscopic follow-up observations. Demographics of the HZ planets are
compared with a full catalog of exoplanets. Extreme planets within the HZ are
highlighted, and how their unique properties may affect their potential
habitability. Kepler-296 f is the most eccentric <2 $R_\oplus$ planet that
spends 100% of its orbit in the HZ. HD 106270 b and HD 38529 c are the most
massive planets (<13 $M_J$) that orbit within the HZ, and are ideal targets for
determining the properties of potential hosts of HZ exomoons. These planets,
along with the others highlighted, will serve as special edge-cases to the
Earth-based scenario and observations of these targets will help test the
resilience of habitability outside the standard model. The most promising
observational HZ target that is known to transit is GJ 414 A b. Of the
transiting, <2 $R_\oplus$ HZ planets, LHS 1140 b, TRAPPIST-1 d and K2-3 d are
the most favorable. Of the non-transiting HZ planets, HD 102365 b and 55 Cnc f
are the most promising, and the best non-transiting candidates that are <2
$R_\oplus$ are GJ 667 C c, Wolf 1061 c, Ross 508 b, Teegarden's Star b, and
Proxima Cen b.
