4 letter words:
fabs9,
fibs9,
fubs9,
aufs7,
bias6,
isba6,
suba6,
3 letter words:
fab8,
fib8,
fub8,
auf6,
fas6,
ifs6,
sif6,
abs5,
bas5,
bis5,
bus5,
sab5,
sib5,
sub5,
ais3,
sai3,
sau3,
sui3,
2 letter words:
fa5,
if5,
ab4,
ba4,
bi4,
ai2,
as2,
is2,
si2,
us2,