  We measure the environmental dependence, where environment is defined by the
distance to the third nearest neighbor, of multiple galaxy properties inside
the Environmental COntext (ECO) catalog. We focus primarily on void galaxies,
which we define as the $10 \%$ of galaxies having the lowest local density. We
compare the properties of void and non-void galaxies: baryonic mass, color,
fractional stellar mass growth rate (FSMGR), morphology, and
gas-to-stellar-mass ratio (estimated from a combination of HI data and
photometric gas fractions calibrated with the RESOLVE survey). Our void
galaxies typically have lower baryonic masses than galaxies in denser
environments, and they display the properties expected of a lower mass
population: they have more late-types, are bluer, have higher FSMGR, and are
more gas rich. We control for baryonic mass and investigate the extent to which
void galaxies are different at fixed mass. Void galaxies are bluer, more
gas-rich, and more star forming at fixed mass than non-void galaxies, which is
a possible signature of galaxy assembly bias. Furthermore, we show that these
trends persist even at fixed mass and morphology, and we find that voids host a
distinct population of early-types that are bluer and more star-forming than
the typical red and quenched early-types. In addition to these empirical
observational results, we also present theoretical results from mock catalogs
with built-in galaxy assembly bias. We show that a simple matching of galaxy
properties to (sub)halo properties, such as mass and age, can recover the
observed environmental trends in ECO galaxies.
