  White dwarf stars are ubiquitous in the Galaxy, and are essential to
understanding stellar evolution. While most white dwarfs are photometrically
stable and reliable flux standards, some can be highly variable, which can
reveal unique details about the endpoints of low-mass stellar evolution. In
this study we characterize a sample of high-confidence white dwarfs with
multi-epoch photometry from Gaia Data Release 3. We compare these Gaia light
curves with light curves from the Zwicky Transiting Facility and the Transiting
Exoplanet Survey Satellite to see when Gaia data independently can accurately
measure periods of variability. From this sample, 105 objects have variability
periods measured from the Gaia light curves independently, with periods as long
as roughly 9.5 d and as short as 256.2 s (roughly 4 min), including seven
systems with periods shorter than 1000 s. We discover 86 new objects from the
105 target sample, including pulsating, spotted, and binary white dwarfs, and
even a new 68.4 min eclipsing cataclysmic variable. The median amplitude of the
absolute photometric variability we confirm from Gaia independently is 1.4%,
demonstrating that Gaia epoch photometry is capable of measuring short-term
periods even when observations are sparse.
