  We present a comprehensive catalog of cool (period $P\gtrsim 2\,\mathrm{yr}$)
transiting planet candidates in the four-year light curves from the prime
\kepler\ mission. Most of the candidates show only one or two transits and have
largely been missed in the original Kepler Object of Interest catalog. Our
catalog is based on all known such candidates in the literature as well as new
candidates from the search in this paper, and provides a resource to explore
the planet population near the snow line of Sun-like stars. We homogeneously
performed pixel-level vetting, stellar characterization with GAIA parallax and
archival/Subaru spectroscopy, and light-curve modeling to derive planet
parameters and to eliminate stellar binaries. The resulting clean sample
consists of 67 planet candidates whose radii are typically constrained to 5\%,
in which 23 are newly reported. The number of Jupiter-sized candidates (29 with
$r>8\,R_\oplus$) in the sample is consistent with the Doppler occurrence. The
smaller candidates are more prevalent (23 with $4<r/R_\oplus<8$, 15 with
$r/R_\oplus<4$) and suggest that long-period Neptune-sized planets are at least
as common as the Jupiter-sized ones, although our sample is yet to be corrected
for detection completeness. If the sample is assumed to be complete, these
numbers imply the occurrence rate of $0.39\pm0.07$ planets with
$4<r/R_\oplus<14$ and $2<P/\mathrm{yr}<20$ per FGK dwarf. The stars hosting
candidates with $r>4\,R_\oplus$ have systematically higher [Fe/H] than the
Kepler field stars, providing evidence that giant planet--metallicity
correlation extends to $P>2\,\mathrm{yr}$.
