Solutions :

3-letter words (1 point): 48

AIM; AIR; AMI; ARB; ARE; ARM; BEE; BEG; BRA; DEE; DEF; DEG; DEI; EGG; ERA; ERE; ERF; FED; FEE; FEG; FEH; FER; FIB; FIE; FIR; GED; GEE; HER; IRE; MAR; MIB; MIR; RAI; RAM; REB; RED; REE; REF; REG; REH; REI; RIA; RIB; RIF; RIM; VIA; VIE; VIM.

4-letter words (1 point): 54

AMIE; AMIR; AREG; BEEF; BEER; BERM; BIER; BIMA; BREE; BREI; BRIE; BRIM; DEER; DEFI; DEIF; DERE; DREE; DREG; EGER; EHED; ERED; FEEB; FEED; FEER; FERE; FERM; FIAR; FIER; FIRE; FIRM; FREE; GEED; GERE; GERM; GHEE; HEED; HEIR; HERB; HERD; HERE; HERM; MAIR; MARE; MIRE; RAMI; REED; REEF; REIF; RIFE; RIMA; VIBE; VIED; VIER; VIRE.

5-letter words (2 points): 21

BREED; BREER; BRIEF; BRIER; DEFER; EGGED; EGGER; ERBIA; FERIA; FERMI; FIBER; FIBRE; FIERE; FREED; FREER; HERMA; MAIRE; RAMIE; REFED; REFER; RIFER.

6-letter words (3 points): 9

BEGGED; DEFIER; DEGERM; DEIFER; HEIFER; HERIED; HERMAI; REEFER; REFIRE.

7-letter words (7 points): 6

AREFIED; BRIEFED; BRIEFER; GERMIER; HERBIER; REEFIER.

8-letter word (11 points): 1

GERMFREE.