Transit ephemerides and timing variations from Kepler and K2 to TESS

We present a catalogue of transiting exoplanetary systems discovered in Kepler or K2 data that were observed again by Transiting Exoplanet Survey Satellite (TESS). The long baseline spanned by the data enabled us to refine ephemerides and orbital parameters, as well as look for long-term non-linear trends in their transit times indicative of transit timing variations (TTVs). In total, we re-examine 111 Kepler or K2 planets. Of these, 11 were known previously to show TTVs. Additionally, we find evidence for either periodic timing residuals or non-linear trends in the ephemerides of 22 planets for which timing variations were not previously detected. Of particular interest are Kepler-522 b, which shows periodic TTVs of 20 min in amplitude, and K2-348 b, one of two transiting Neptune-sized planets in the system for which TESS data shows long-term second-order trends. For all planets, we report an update to their linear ephemerides with an improvement in the precision of the period by a factor of 2-10.