6 letter words:
refire9,
5 letter words:
ferer8,
fiere8,
firer8,
freer8,
frere8,
frier8,
refer8,
rifer8,
4 letter words:
feer7,
fere7,
fier7,
fire7,
free7,
reef7,
reif7,
rife7,
3 letter words:
erf6,
fee6,
fer6,
fie6,
fir6,
ref6,
rif6,
ere3,
err3,
ire3,
ree3,
rei3,
2 letter words:
ef5,
fe5,
if5,
ee2,
er2,
re2,