  Close binary systems are the progenitors to both Type Ia supernovae and the
compact object mergers that can be detected via gravitational waves. To achieve
a binary with a small radial separation, it is believed that the system likely
undergoes common envelope (CE) evolution. Despite its importance, CE evolution
may be one of the largest uncertainties in binary evolution due to a
combination of computational challenges and a lack of observed benchmarks where
both the post-CE and pre-CE conditions are known. Identifying post-CE systems
in star clusters can partially circumvent this second issue by providing an
independent age constraint on the system. For the first time, we conduct a
systematic search for white dwarf (WD) and main-sequence (MS) binary systems in
299 Milky Way open star clusters. Coupling Gaia DR3 photometry and kinematics
with multi-band photometry from Pan-STARRS1 and 2MASS, we apply a machine
learning based approach and find 52 high-probability candidates in 38 open
clusters. For a subset of our systems, we present follow-up spectroscopy from
the Gemini and Lick Observatories and archival light curves from TESS,
Kepler/K2 and the Zwicky Transient Facility. Examples of M-dwarfs with hot
companions are spectroscopically observed, along with regular system
variability. While the kinematics of our candidates are consistent with their
host clusters, some systems have spatial positions offset relative to their
hosts, potentially indicative of natal kicks. Ultimately, this catalogue is a
first step to obtaining a set of observational benchmarks to better link
post-CE systems to their pre-CE progenitors.
