4 letter words:
beef9,
feeb9,
feen7,
feer7,
fere7,
fern7,
free7,
reef7,
been6,
beer6,
bene6,
bere6,
bree6,
bren6,
erne4,
reen4,
3 letter words:
erf6,
fee6,
fen6,
fer6,
nef6,
ref6,
bee5,
ben5,
neb5,
reb5,
een3,
ene3,
ere3,
ern3,
nee3,
ree3,
ren3,
2 letter words:
ef5,
fe5,
be4,
ee2,
en2,
er2,
ne2,
re2,