use '?' for JOKER (blank)

From letters K, I, E, S, T, E, R, S  I made following words

8 letter words

keisters[12], kiesters[12]

7 letter words

keister[11], kiester[11], streeks[11], strikes[11], resites[7]

6 letter words

eskers[10], kisser[10], krises[10], skiers[10], streek[10], kiters[10], strike[10], trikes[10], skeets[10], steeks[10], skites[10], skirts[10], stirks[10], seiser[6], series[6], sirees[6], resite[6], reties[6], esters[6], reests[6], resets[6], serest[6], steers[6], steres[6], resist[6], resits[6], sister[6]

5 letter words

esker[9], reeks[9], keirs[9], kiers[9], siker[9], skier[9], seeks[9], skees[9], sikes[9], skies[9], risks[9], kiter[9], trike[9], keets[9], skeet[9], steek[9], kites[9], skite[9], tikes[9], treks[9], skirt[9], stirk[9], kists[9], skits[9], siree[5], seise[5], erses[5], seers[5], seres[5], rises[5], sires[5], retie[5], ester[5], reest[5], reset[5], steer[5], stere[5], terse[5], trees[5], resit[5], rites[5], tiers[5], tires[5], tries[5], sites[5], sties[5], rests[5], tress[5], stirs[5]

4 letter words

reek[8], keir[8], kier[8], ekes[8], seek[8], skee[8], sike[8], irks[8], kirs[8], kris[8], risk[8], kiss[8], skis[8], keet[8], kite[8], tike[8], trek[8], kist[8], kits[8], skit[8], tsks[8], rees[4], seer[4], sere[4], ires[4], reis[4], rise[4], sire[4], eses[4], sees[4], seis[4], sers[4], sirs[4], sris[4], rete[4], tree[4], rite[4], tier[4], tire[4], tees[4], site[4], ties[4], erst[4], rest[4], rets[4], tres[4], stir[4], sets[4], sits[4]

3 letter words

eek[7], eke[7], irk[7], kir[7], kis[7], ski[7], kit[7], tsk[7], ere[3], ree[3], ire[3], rei[3], see[3], sei[3], ers[3], res[3], ser[3], sir[3], sri[3], ess[3], sis[3], tee[3], tie[3], ret[3], set[3], its[3], sit[3], tis[3]

2 letter words

ki[6], er[2], re[2], es[2], is[2], si[2], et[2], it[2], ti[2]