4 letter words:
beef9,
feeb9,
feer7,
fere7,
free7,
reef7,
beer6,
bere6,
bree6,
rube6,
3 letter words:
fub8,
erf6,
fee6,
fer6,
feu6,
fur6,
ref6,
bee5,
bru5,
bur5,
reb5,
rub5,
urb5,
ere3,
ree3,
rue3,
ure3,
2 letter words:
ef5,
fe5,
be4,
ee2,
er2,
re2,
ur2,