use '?' for JOKER (blank)

From letters B, A, C, K, G, R, O, U, N, D, E, R, S  I made following words

13 letter words

backgrounders[23]

12 letter words

backgrounder[22]

11 letter words

backgrounds[21]

10 letter words

background[20], cornbreads[15], curanderos[13]

9 letter words

brockages[18], cankerous[15], cornbread[14], absconder[14], subdeacon[14], scrounged[13], curandero[12], rancoured[12], unscarred[12], scrounger[12], dangerous[11], noseguard[11], grandeurs[11], grounders[11]

8 letter words

brockage[17], bedrocks[17], unbacked[17], burdocks[17], dockages[16], brackens[16], geoducks[16], runbacks[16], roebucks[16], brokages[15], grosbeak[15], corkages[15], dornecks[15], unbraked[15], uncorked[15], sunbaked[15], uncasked[15], croakers[14], unbrakes[14], crankous[14], brocades[13], unbraced[13], abducens[13], unsoaked[13], cudbears[13], obscured[13], bondages[12], dogbanes[12], decagons[12], cordages[12], braceros[12], ungarbed[12], ungraced[12], subocean[12], subgrade[12], unbraces[12], scourged[12], scrouged[12], bouncers[12], obscurer[12], rancored[11], bandores[11], broadens[11], endosarc[11], begroans[11], acrogens[11], branders[11], adsorber[11], boarders[11], reboards[11], corrades[11], unbarred[11], arboured[11], durances[11], caroused[11], courages[11], baudrons[11], candours[11], bounders[11], rebounds[11], suborned[11], crunodes[11], osnaburg[11], burgeons[11], scrounge[11], absurder[11], crusader[11], sandburr[11], bordures[11], suborder[11], scourger[11], grandeur[10], grounder[10], reground[10], nacreous[10], guerdons[10], guarders[10], gurnards[10], carouser[10], rancours[10], suborner[10], adorners[9], readorns[9], groaners[9], rondures[9], rounders[9]

7 letter words

bedrock[16], dockage[15], bracken[15], beckons[15], backers[15], cranked[14], croaked[14], brokage[14], corkage[14], dorneck[14], snacked[14], boskage[14], debarks[14], dackers[14], dockers[14], redocks[14], cranker[13], croaker[13], bankers[13], cankers[13], snacker[13], bonkers[13], conkers[13], brocade[12], knarred[12], boscage[12], abscond[12], darkens[12], bondage[11], dogbane[11], congaed[11], decagon[11], cordage[11], bracero[11], bodegas[11], beacons[11], bandogs[11], badgers[11], cadgers[11], boraces[11], codgers[11], carbons[11], corbans[11], bandore[10], broaden[10], acorned[10], begroan[10], acrogen[10], brander[10], arbored[10], boarder[10], broader[10], reboard[10], corrade[10], begorra[10], acnodes[10], deacons[10], nosebag[10], banders[10], dancers[10], bangers[10], grabens[10], borages[10], cargoes[10], corsage[10], socager[10], robands[10], candors[10], cardons[10], dacrons[10], bonders[10], scorned[10], barongs[10], brogans[10], garcons[10], congers[10], groaned[9], gnarred[9], grander[9], dangers[9], ganders[9], gardens[9], dogears[9], boranes[9], canoers[9], coarsen[9], corneas[9], narcose[9], dragons[9], adorner[8], readorn[8], groaner[8], onagers[8], oranges[8]