7 letter words:
reefers10,
6 letter words:
freers9,
freres9,
reefer9,
refers9,
5 letter words:
feers8,
feese8,
ferer8,
feres8,
freer8,
frees8,
frere8,
reefs8,
refer8,
sefer8,
resee5,
serer5,
serre5,
4 letter words:
feer7,
fees7,
fere7,
free7,
reef7,
refs7,
serf7,
eres4,
errs4,
rees4,
seer4,
sere4,
serr4,
3 letter words:
efs6,
erf6,
fee6,
fer6,
fes6,
ref6,
ere3,
err3,
ers3,
ree3,
res3,
see3,
ser3,
2 letter words:
ef5,
fe5,
ee2,
er2,
es2,
re2,