  In a recent work, Beierle, Brinkmann and Leander presented a recursive tree
search for finding APN permutations with linear self-equivalences in small
dimensions. In this paper, we describe how this search can be adapted to find
many new instances of quadratic APN functions. In particular, we found 12,921
new quadratic APN functions in dimension eight, 35 new quadratic APN functions
in dimension nine and five new quadratic APN functions in dimension ten up to
CCZ-equivalence. Remarkably, two of the 35 new APN functions in dimension nine
are APN permutations.
  Among the 8-bit APN functions, there are three extended Walsh spectra that do
not correspond to any of the previously-known quadratic 8-bit APN functions
and, surprisingly, there exist at least four CCZ-inequivalent 8-bit APN
functions with linearity $2^7$, i.e., the highest possible non-trivial
linearity for quadratic functions in dimension eight.
