2 letters:
et

3 letters:
bet, get, jet, let, met, net, pet, ret, set, tet, vet, wet, yet

4 letters:
abet, bret, debt, duet, fret, lett, nett, piet, stet, tete, viet, whet

5 letters:
-ette, alfet, armet, asset, beget, beset, bizet, brett, cadet, caret, godet, inlet, inset, motet, octet, onset, pipet, reset, revet, sweat, tebet, tibet, unset, upset

6 letters:
arcnet, arnett, as yet, avocet, bitnet, biuret, brevet, brunet, cermet, chevet, cornet, duette, forget, gimlet, joliet, juliet, labret, lanset, lionet, minuet, offset, outlet, outset, placet, poulet, preset, projet, rachet, ramjet, regret, rillet, septet, sestet, sextet, soviet, spinet, sublet, subset, sunset, telnet, threat, tv set, usenet

7 letters:
aldomet, alkanet, annette, arpanet, backset, baronet, basinet, bayonet, beignet, biegnet, boneset, bosquet, burette, burnett, calumet, casquet, cigaret, colette, coronet, curette, cuvette, dinette, doublet, dragnet, epaulet, epithet, gas jet, gazette, hairnet, handset, headset, isohyet, jaconet, jet set, josette, kinglet, layette, lorette, low-set, lunette, minaret, mindset, minette, moonset, musette, not yet, octette, overset, parapet, pipette, propjet, quartet, quintet, ringlet, rosette, satinet, saw set, tagamet, tea set, twinjet, typeset, vedette, vidette, vilayet, wavelet, winglet, woodlet, wordnet, you bet

8 letters:
aigrette, alphabet, anisette, bad debt, baguette, ballonet, baphomet, barbette, barrette, brunette, burgonet, canzonet, carcanet, cassette, castanet, clarinet, coquette, corvette, coverlet, dead set, deep-set, diskette, dragonet, ethernet, extranet, falconet, gill net, heavyset, internet, jeanette, maquette, marmoset, martinet, mind-set, moquette, muscadet, noisette, null set, pallette, palmette, poulette, quickset, raclette, rondolet, roomette, roquette, roulette, sarcenet, sarsenet, septette, serpolet, sextette, shrublet, somerset, superhet, swiftlet, tabouret, thickset, toucanet, turbojet, underlet, vignette, well-set

9 letters:
briquette, brochette, cabriolet, cassoulet, chess set, chevrette, cigarette, close-set, close set, couchette, courgette, croquette, drift net, epaulette, flageolet, georgette, jeannette, lafayette, lazarette, lorgnette, marquette, midinette, novelette, oubliette, place bet, pound net, quartette, quintette, quodlibet, radio set, roussette, sharp-set, smart set, sobriquet, soubrette, springlet, stage set, statuette, stockinet, summerset, thermoset, usherette, videlicet

10 letters:
aiguilette, analphabet, bernadette, blanquette, carbon tet, cassolette, cold sweat, dinner set, farmerette, fourchette, horsey set, marionette, paramagnet, planchette, silhouette, sneakernet, sulfurette, winceyette

11 letters:
aiguillette, bedroom set, fishing net, kitchenette, landing net, launderette, leatherette, maisonnette, oxygen debt, plantagenet, public debt, rambouillet, stockinette, suffragette, sulphurette, tete-a-tete, vinaigrette

12 letters:
bachelorette, bouncing bet, exercise set, liquid asset, luncheonette, mosquito net, photo-offset, sales outlet

13 letters:
audiocassette, bass clarinet, character set, crepe suzette, line roulette, lion marmoset, national debt, receiving set, reserve asset, stomach upset, telephone set, true marmoset, videocassette

14 letters:
greek alphabet, livingroom set, pygmy marmoset, roman alphabet, sound alphabet, string quartet, television set

15 letters:
arabic alphabet, electric outlet, finger alphabet, hebrew alphabet, manual alphabet, spanish bayonet

16 letters:
capital of tibet, installment debt, intangible asset

17 letters:
armenian alphabet, cyrillic alphabet, phonetic alphabet

19 letters:
ascii character set, marijuana cigarette

20 letters:
hail-fellow-well-met

22 letters:
letter of the alphabet, without becoming upset

8 letters:
mantelet, manifest, alkahest

10 letters:
battlement