7 letter words:
beerier9,
burrier9,
6 letter words:
burier8,
burrer8,
rubier8,
eerier6,
5 letter words:
brier7,
eerie5,
4 letter words:
beer6,
bier6,
birr6,
bree6,
brie6,
brrr6,
burr6,
rube6,
ruer4,
3 letter words:
bee5,
brr5,
bur5,
reb5,
rib5,
rub5,
urb5,
ere3,
err3,
ire3,
ree3,
rei3,
rue3,
2 letter words:
be4,
bi4,
er2,
re2,