use '?' for JOKER (blank)

From letters K, I, N, D, E, R, G, A, R, T, N, E, R, S  I made following words

14 letter words

kindergartners[20]

13 letter words

kindergartner[19], kindergartens[19]

12 letter words

kindergarten[18]

11 letter words

ringstraked[17], intergrades[13], transgender[13], rearresting[12]

10 letter words

grenadines[12], serenading[12], grenadiers[12], rereadings[12], renderings[12], derringers[12], intergrade[12], retreading[12], denigrates[12], integrands[12], strangered[12], interregna[11], argentines[11], tangerines[11], irredentas[11], restrained[11], entrainers[10], errantries[10], restrainer[10]

9 letter words

darkening[15], gennakers[14], darkeners[14], streaking[14], streeking[14], ankerites[13], streakier[13], tinkerers[13], endearing[11], engrained[11], grenadine[11], earringed[11], grenadier[11], rereading[11], rendering[11], derringer[11], gesneriad[11], endangers[11], greensand[11], resending[11], derangers[11], gardeners[11], grandsire[11], deringers[11], denigrate[11], gratineed[11], integrand[11], tendering[11], regranted[11], retarding[11], deterring[11], designate[11], tragedies[11], estranged[11], astringed[11], gradients[11], deserting[11], stranding[11], reearning[10], regainers[10], entrained[10], argentine[10], tangerine[10], irredenta[10], retrained[10], retearing[10], rerenting[10], antigenes[10], detainers[10], resinated[10], agentries[10], gratinees[10], reseating[10], stingaree[10], transgene[10], indenters[10], intenders[10], gannister[10], renesting[10], resenting[10], dreariest[10], estranger[10], instarred[10], arresting[10], serrating[10], retarders[10], registrar[10], entrainer[9], tanneries[9], retainers[9], ternaries[9]

8 letter words

kneading[14], gennaker[13], darkener[13], sneaking[13], kneaders[13], deerskin[13], rankings[13], drinkers[13], tinkered[13], retaking[13], nakedest[13], steeking[13], inkstand[13], sneakier[12], snarkier[12], ankerite[12], tinkerer[12], neatniks[12], regained[10], endanger[10], deranger[10], gardener[10], garnered[10], deringer[10], disagree[10], deranges[10], grandees[10], grenades[10], deraigns[10], gradines[10], readings[10], designer[10], energids[10], redesign[10], reedings[10], resigned[10], darnings[10], regrades[10], grandsir[10], grinders[10], regrinds[10], derating[10], gradient[10], redating[10], treading[10], trending[10], garreted[10], gartered[10], regrated[10], sedating[10], steading[10], ingested[10], signeted[10], standing[10], restaged[10], regainer[9], drearier[9], adenines[9], arsenide[9], nearside[9], anergies[9], gesneria[9], ensnared[9], insnared[9], aginners[9], earnings[9], engrains[9], grannies[9], sneering[9], drearies[9], reraised[9], greasier[9], drainers[9], serranid[9], earrings[9], grainers[9], resigner[9], grinners[9], antigene[9], detainer[9], retained[9], gratinee[9], interage[9], indenter[9], intender[9], interned[9], entering[9], interred[9], trendier[9], retarder[9], andesite[9], dentines[9], desinent[9], antigens[9], gentians[9], readiest[9], seriated[9], anserine[8], ensnarer[8], insnarer[8], retainer[8], inerrant[8]