We distribute a preliminary Fermi Large Area Telescope list of sources
(FL8Y) initially meant to help in writing 2018 NASA Fermi Guest Investigator
proposals. Based on the first eight years of science data from the
Fermi Gamma-ray Space Telescope mission and the 100 MeV-1 TeV range, it
is the deepest yet in this energy range. Relative to the 3FGL catalog,
the FL8Y source list has twice as much exposure as well as a number of
analysis improvements, but is lacking an updated model for Galactic
diffuse gamma-emission.  The FL8Y source list includes 5523 sources
above 4sigma significance, with source location regions and spectral
properties. Fifty-eight sources are modeled explicitly as spatially
extended, and overall 300 sources are considered as identified based
on angular extent or correlated variability (periodic or otherwise)
observed at other wavelengths. For 2131 sources we have not found
plausible counterparts at other wavelengths. More than 2900 of the
identified or associated sources are active galaxies of the blazar class,
218 are pulsars.  This source list is meant to be replaced within a few
months by the official 4FGL catalog which will benefit from an improved
model of diffuse emission.