  The rotation periods of the magnetic Ap stars span five to six orders of
magnitude. Period differentiation must have taken place at the pre-main
sequence stage, but the physical processes that lead to it remain elusive. The
study of Ap stars that have rotation periods of tens to hundreds of years
represents a promising avenue to gain additional insight into the origin and
evolution of rotation in Ap stars.
  Historically, almost all the longest period Ap stars known have been found to
be strongly magnetic; very few weakly magnetic Ap stars with very long periods
have been identified and studied. We performed a systematic search based on
TESS data to identify super-slowly rotating Ap (ssrAp) stars independently of
the strengths of their magnetic fields, with the intention to characterise the
distribution of the longest Ap star rotation periods in an unbiased manner. We
find 67 Ap stars with no rotational variability in the northern ecliptic
hemisphere TESS data. Among them, 46 are newly identified ssrAp star
candidates, which is double the number previously found in the southern
ecliptic hemisphere.
  We confirm that super-slow rotation tends to occur less frequently in weakly
magnetic Ap stars than in strongly magnetic stars. We present new evidence of
the existence of a gap between ~2 kG and ~3 kG in the distribution of the
magnetic field strengths of long period Ap stars. We also confirm that the
incidence of roAp stars is higher than average in slowly rotating Ap stars. We
report the unexpected discovery of nine definite and five candidate {\delta}
Sct stars, and of two eclipsing binaries. This work paves the way for a
systematic, unbiased study of the longest period Ap stars, with a view to
characterise the correlations between their rotational, magnetic, and
pulsational properties.
