6 letter words:
effere12,
reefer9,
5 letter words:
ferer8,
freer8,
frere8,
refer8,
4 letter words:
feer7,
fere7,
free7,
reef7,
eger5,
gere5,
gree5,
3 letter words:
eff9,
feg7,
erf6,
fee6,
fer6,
ref6,
erg4,
gee4,
reg4,
ere3,
err3,
ree3,
2 letter words:
ef5,
fe5,
ee2,
er2,
re2,