Solutions :

3-letter words (1 point): 48

AIR; AIS; ARB; ARD; ARE; ARS; BED; BEE; BRA; BUD; CEE; CUB; CUD; CUE; DAE; DAS; DEB; DEE; DEI; DUB; DUE; EAR; EAS; ECU; ERA; ERE; ERS; ICE; IRE; PIC; PIR; RAD; RAI; RAS; REB; REC; RED; REE; REI; RIA; RIB; RIP; SAD; SAE; SAI; SAR; SIR; SRI.

4-letter words (1 point): 62

AIRS; ARED; ARIS; BEAD; BEAR; BEDE; BEDU; BERE; BICE; BIER; BIRD; BRAD; BRAE; BRAS; BRED; BREE; BREI; BRER; BRIE; BRIS; BUDA; CEAS; CEDE; CERE; CIRE; CUBE; CUED; DAIS; DARB; DARE; DARI; DEAR; DEER; DERE; DREE; DRIB; DUCE; DUCI; EARD; EARS; ERAS; ERED; ERIC; ICED; ICER; IRED; IRIS; PICE; RADE; RAIS; READ; REDE; REED; REIS; RIAS; RICE; SADE; SAIR; SARD; SARI; SIRE; SIRI.

5-letter words (2 points): 45

AERIE; AIRED; AIRER; ARDEB; AREDE; ARERE; BEARD; BEARE; BEARS; BIERS; BREAD; BREDE; BREED; BREER; BREIS; BRERE; BRERS; BRIER; BUDAS; CEDAR; CERIA; CUBED; CUBER; DARER; DARIS; DEAIR; DEARE; DEARS; DEERE; DEERS; DEUCE; DRERE; DRIER; EDUCE; EERIE; ICERS; IRADE; REDUB; REIRD; RICED; RICER; SARED; SAREE; SIRED; SIREE.

6-letter words (3 points): 22

AERIER; AIRIER; ARSIER; BEARER; BREERS; BRIERS; CEDARS; CERIAS; CUBERS; DEAIRS; DEARER; DEARIE; DEBRIS; EARBUD; EASIER; EERIER; IBERIS; REREAD; RIBIER; RICERS; SAIRED; SAIRER.

7-letter words (7 points): 5

BIRSIER; BRASIER; BREERED; BRIERED; RIBIERS.

8-letter word (11 points): 1

RICEBIRD.