  Stellar variability studies are now reaching a completely new level thanks to
ESA's Gaia mission, which enables us to locate many variable stars in the
Hertzsprung-Russell diagram and determine the various instability strips/bands.
Furthermore, this mission also allows us to detect, characterise and classify
many millions of new variable stars thanks to its very unique nearly
simultaneous multi-epoch survey with different instruments (photometer,
spectro-photometer, radial velocity spectrometer). An overview of what can be
found in literature in terms of mostly data products by the Gaia consortium is
given. This concerns the various catalogues of variable stars derived from the
Gaia time series and also the location and motion of variable stars in the
observational Hertzsprung-Russell diagram. In addition, we provide a list of a
few thousands of variable white dwarf candidates derived from the DR2 published
data, among them probably many hundreds of new pulsating white dwarfs. On a
very different topic, we also show how Gaia allows us to reveal the 3D
structures of and around the Milky Way thanks to the RR Lyrae stars.
