  The very massive first stars ($m>100\rm M_{\odot}$) were fundamental to the
early phases of reionization, metal enrichment, and super-massive black hole
formation. Among them, those with $140\leq\rm m/\rm M_{\odot}\leq260$ are
predicted to evolve as Pair Instability Supernovae (PISN) leaving a unique
chemical signature in their chemical yields. Still, despite long searches, the
stellar descendants of PISN remain elusive. Here we propose a new methodology,
the PISN-explorer, to identify candidates for stars with a dominant PISN
enrichment. The PISN-explorer is based on a combination of physically driven
models, and the FERRE code; and applied to data from large spectroscopic
surveys (APOGEE, GALAH, GES, MINCE, and the JINA database). We looked into more
than 1.4 million objects and built a catalogue with 166 candidates of PISN
descendants. One of which, 2M13593064+3241036, was observed with UVES at VLT
and full chemical signature was derived, including the killing elements, Cu and
Zn. We find that our proposed methodology is efficient in selecting PISN
candidates from both the Milky Way and dwarf satellite galaxies such as Sextans
or Draco. Further high-resolution observations are highly required to confirm
our best selected candidates, therefore allowing us to probe the existence and
properties of the very massive First Stars.
