5 letter words:
offer11,
reffo11,
freon8,
4 letter words:
feen7,
feer7,
fere7,
fern7,
foen7,
fone7,
fore7,
free7,
froe7,
orfe7,
reef7,
erne4,
oner4,
reen4,
rone4,
3 letter words:
eff9,
off9,
erf6,
fee6,
fen6,
fer6,
foe6,
fon6,
for6,
fro6,
nef6,
orf6,
ref6,
een3,
ene3,
eon3,
ere3,
ern3,
nee3,
nor3,
one3,
ore3,
ree3,
ren3,
reo3,
roe3,
2 letter words:
ef5,
fe5,
of5,
ee2,
en2,
er2,
ne2,
no2,
oe2,
on2,
or2,
re2,