5 letter words:
ferer8,
freer8,
frere8,
refer8,
4 letter words:
feen7,
feer7,
fere7,
fern7,
free7,
reef7,
erne4,
reen4,
3 letter words:
erf6,
fee6,
fen6,
fer6,
nef6,
ref6,
een3,
ene3,
ere3,
ern3,
err3,
nee3,
ree3,
ren3,
2 letter words:
ef5,
fe5,
ee2,
en2,
er2,
ne2,
re2,