  Astrophysical plasma codes are built on atomic databases. In the current
atomic databases, R-matrix electron-impact excitation data of O-like ions are
limited. The accuracy of plasma diagnostics with O-like ions depends on the
availability and accuracy of the atomic data. This is particularly relevant in
the context of future observatories equipped with the next generation of
high-resolution spectrometers. To obtain level-resolved effective collision
strengths of O-like ions from \ion{Ne}{III} to \ion{Zn}{XXIII} (i.e., Ne$^{2+}$
to Zn$^{22+}$) over a wide range of temperatures. This includes transitions up
to $nl=5d$ for each ion. We also aim to assess the accuracy of the new data, as
well as their impact on solar atmosphere plasma diagnostics, compared to those
available within the CHIANTI database. A large-scale R-matrix intermediate
coupling frame transformation calculations were performed systematically for
the O-like iso-electronic sequence. For each ion, 630 fine-structure levels
were included in both the configuration interaction target and close-coupling
collision expansions. The present results (energy levels, oscillator strengths,
and effective collision strengths) of selected ions across the iso-electronic
sequence are compared with those in archival databases and the literature. For
selected ions across the iso-electronic sequence. We find general agreement
with the few previous R-matrix calculations of collision strengths. We
illustrate the improvements for a few solar plasma diagnostics over existing
CHIANTI atomic models based on distorted wave data. The electron-impact
excitation data are archived according to the Atomic Data and Analysis
Structure (ADAS) data class adf04 and will be available in OPEN-ADAS.
