  We study the flavor structure of the lepton and baryon number--conserving
dimension-6 operators in the Standard Model effective field theory (SMEFT).
Building on the work of [1], we define several well-motivated flavor symmetries
and symmetry-breaking patterns that serve as competing hypotheses about the
ultraviolet (UV) dynamics beyond the SM, not far above the TeV scale. In
particular, we consider four different structures in the quark sector and seven
in the charged lepton sector. The set of flavor-breaking spurions is (almost)
always taken to be the minimal one needed to reproduce the observed charged
fermion masses and mixings. For each case, we explicitly construct and count
the operators to the first few orders in the spurion expansion, providing
ready-for-use setups for phenomenological studies and global fits. We provide a
Mathematica package SMEFTflavor to facilitate similar analyses for flavor
symmetries not covered in this work.
