5 letters:
aster, astor, astur

6 letters:
-aster, bastar, baster, caster, castor, dastar, dastur, faster, gaster, haster, hastur, jaster, kaster, kastor, laster, lastre, master, mastor, paster, pastor, raster, sastre, vaster

7 letters:
-master, blaster, craster, diaster, pasztor, piaster, plaster, shaster

8 letters:
albastar, ancaster, cadaster, canaster, cast her, drmaster, mcmaster, oleaster, past her, pflaster, pilaster, remaster, solaster, unpastor

9 letters:
adelaster, alabaster, ari aster, barmaster, beemaster, beplaster, bog aster, botmaster, doncaster, emplaster, lancaster, macmaster, micraster, mixmaster, myocastor, netcaster, paymaster, pineaster, podcaster, saymaster, sea aster, spymaster, stylaster, tadcaster, warmaster, waycaster, webcaster, webmaster

10 letters:
amphiaster, bandmaster, bergmaster, brewmaster, buckmaster, burgmaster, bushmaster, cluemaster, cockmaster, contraster, divemaster, dockmaster, dvdisaster, firemaster, forecaster, gamemaster, gangmaster, goodpaster, hackmaster, headmaster, hoffmaster, huffmaster, ink master, ironmaster, jazzmaster, judomaster, jumpmaster, landmaster, linecaster, loadmaster, lockmaster, medicaster, mesogaster, newscaster, old master, overmaster, passed her, postmaster, quizmaster, ringmaster, roadmaster, rolemaster, rush aster, shipmaster, surfcaster, taskmaster, telecaster, two-master, wood aster, workmaster, yardmaster

11 letters:
azure aster, beachmaster, beach aster, beastmaster, broadcaster, burghmaster, burgomaster, bushy aster, chessmaster, china aster, choirmaster, criticaster, drillmaster, fightmaster, flamemaster, gamesmaster, genus aster, grandmaster, grassmaster, heath aster, housemaster, jewelmaster, mint-master, nightcaster, past master, rangemaster, roughcaster, sambomaster, sandblaster, scoutmaster, sheepmaster, shinplaster, slavemaster, spellcaster, sperm-aster, stainmaster, stairmaster, stiff aster, supertaster, toastmaster, trackmaster, trainmaster, undermaster, view-master, watermaster, weighmaster, wharfmaster, wheremaster, whoremaster, witticaster, yachtmaster

12 letters:
bargemastter, calico aster, chargemaster, craftsmaster, drill master, games-master, genus castor, golden aster, harbormaster, mojave aster, politicaster, puppetmaster, puzzlemaster, schoolmaster, smooth aster, snallygaster, solenogaster, sportscaster, sportsmaster, sticky aster, stratocaster, thrustmaster, ticketmaster, willow aster, wreck-master

13 letters:
boroughmaster, burghermaster, concertmaster, countercaster, court-plaster, court plaster, ghettoblaster, harbourmaster, interpilaster, james acaster, prairie aster, quartermaster, rebroadcaster, riding master, servicemaster, starved aster, stationmaster, weathercaster

14 letters:
aromatic aster, avro lancaster, concert-master, dancing-master, grammaticaster, henry mcmaster, jim buckmaster, new york aster, sailing master, singing-master, southern aster, verticillaster

15 letters:
mustard plaster, property master, question master

16 letters:
adhesive plaster, cornflower aster, goldilocks aster, lath and plaster, sticking-plaster, sticking plaster, tansy leaf aster, white wood aster

17 letters:
city of lancaster, late purple aster, new england aster, small white aster

18 letters:
hairy golden aster, house of lancaster, oriental alabaster, rattlesnake master, upland white aster, weather forecaster

19 letters:
paco cabanes pastor, white prairie aster

20 letters:
prairie golden aster

21 letters:
eastern silvery aster, maryland golden aster, television newscaster, western silvery aster

26 letters:
perennial salt marsh aster

5 letters:
after, asker, asper

6 letters:
lascar, caspar, rafter, casper, jasper

7 letters:
drafter, crafter

8 letters:
laughter, go after, be after

9 letters:
hereafter

10 letters:
madagascar, take after, basseterre, look after, thereafter, come after, lech after, lust after

11 letters:
chase after, hereinafter, point after, quest after

12 letters:
sought after