  Emission and absorption features from C-like ions serve as temperature and
density diagnostics of astrophysical plasmas. $R$-matrix electron-impact
excitation data sets for C-like ions in the literature merely cover a few ions,
and often only for the ground configuration. Our goal is to obtain
level-resolved effective collision strength over a wide temperature range for
C-like ions from \ion{N}{II} to \ion{Kr}{XXXI} (i.e., N$^{+}$ to Kr$^{30+}$)
with a systematic set of $R$-matrix calculations. We also aim to assess their
accuracy. For each ion, we included a total of 590 fine-structure levels in
both the configuration interaction target and close-coupling collision
expansion. These levels arise from 24 configurations $2l^3 nl^{\prime}$ with
$n=2-4$, $l=0-1$, and $l^{\prime}=0-3$ plus the three configurations $2s^22p5l$
with $l=0-2$. The AUTOSTRUCTURE code was used to calculate the target
structure. Additionally, the $R$-matrix intermediate coupling frame
transformation method was used to calculate the collision strengths. We compare
the present results of selected ions with archival databases and results in the
literature. The comparison covers energy levels, transition rates, and
effective collision strengths. We illustrate the impact of using the present
results on an \ion{Ar}{xiii} density diagnostic for the solar corona. The
electron-impact excitation data is archived according to the Atomic Data and
Analysis Structure (ADAS) data class adf04 and will be available in OPEN-ADAS.
The data will be incorporated into spectral codes, such as CHIANTI and SPEX,
for plasma diagnostics.
