2 letters:
oi, oy

3 letters:
boy, doi, foy, hoi, hoy, joy, loy, moy, neu, oie, oye, roi, roy, soy, toy, woy, yoy

4 letters:
ahoy, boye, broy, choi, choy, cloy, coye, croy, floy, foie, foye, hoye, joye, knoy, kroy, loye, moye, ploy, roye, stoy, toye, troy

5 letters:
abloy, accoy, alcoy, alloy, alroy, annoy, besoi, cfroi, choix, croix, deboy, decoy, dejoy, deut-, elroy, enjoi, enjoy, envoi, estoy, gmroi, ixoye, kagoy, laboy, lafoy, lavoy, leroi, leroy, matoi, mccoy, mckoy, mcroy, mcvoy, moroi, n-joi, namoi, nesoi, nimoy, nomoi, poboy, savoy, scheu, sgroi, stroy, suboi, topoi, u-roy, usdoi, yayoi

6 letters:
accloy, borzoi, boxboy, busboy, calboy, carboy, chamoy, chinoy, convoy, cowboy, dayboy, delroy, deploy, devroy, digboi, ellroy, emploi, employ, eyetoy, femboy, fermoy, gilroy, i'itoi, joeboy, kilroy, konoye, kouroi, lamboy, lenvoi, malloy, mcavoy, mccloy, mcevoy, melroy, milroy, mobvoi, monroy, mulroy, musgoi, mythoi, norroy, octroi, octroy, owlboy, pakhoi, pithoi, polloi, pomroy, psiloi, quemoy, renvoi, rocroi, shamoy, sukhoi, tatsoi, tholoi, toitoi, tomboy, tsuboi, uncoif, ventoy, zomboy

7 letters:
abscheu, aizanoi, albanoi, attaboy, bat boy, bavaroy, beffroi, bellboy, bellroy, bolshoi, brayboy, bushboy, callboy, candroy, chinmoy, chinois, destroy, deveroy, didicoy, domovoi, domovoy, employe, fantroy, farmboy, fitzroy, gameboy, hellboy, highboy, hoichoi, homeboy, honeoye, kadikoy, kaiapoi, kim-joy, lacroix, lovejoy, malavoi, mcelroy, mcilroy, mcinroy, minicoy, montjoy, montroy, niteroi, old boy, oneiroi, overjoy, pageboy, pakchoi, palitoy, playboy, plowboy, polevoi, pomeroy, popejoy, reenjoy, rob roy, spartoi, strigoi, surcloy, synctoy, tallboy, tolstoi, tolstoy, vanscoy, vickroy

8 letters:
ballyvoy, ball boy, baudroie, beachboy, bogazkoy, bok choi, bok choy, canticoy, carquois, city boy, corduroy, cunjevoi, dalstroy, diddicoy, doughboy, erminois, eysturoy, farm boy, fauntroy, flournoy, gilderoy, henchboy, houseboy, illinois, iroquois, kablooie, khoikhoi, kill-joy, kingaroy, lisa joy, maccaboy, macintoy, mafiaboy, malinois, mountjoy, northboi, omphaloi, overcloy, pak-choi, poor boy, redeploy, reemploy, shop boy, stanovoi, steamboy, streymoy, unemploy, vver-toi, whiteboy, wolf boy, zircaloy

9 letters:
altar boy, beregovoy, cabin boy, charleroi, disemploy, kamilaroi, littleboy, men-yoroi, misemploy, nictheroy, ploughboy, preemploy, re-employ, schoolboy, shadertoy, sonny boy, stableboy, stonebwoy, teddy boy, tinkertoy, water boy

10 letters:
athinganoi, catholicoi, claire foy, dauphinois, errand boy, fauntleroy, golden boy, hoi polloi, mama's boy, office boy, pronephroi, real mccoy, rougecroix, sailor boy, wonder boy

11 letters:
college boy, drummer boy, express joy, grocery boy, hors-la-loi, ken mcelroy, leo tolstoy, melanochroi, mesonephroi, metanephroi, turkana boy, underemploy, xanthochroi

12 letters:
backroom boy, delivery boy, elevator boy, jump for joy, kevin conroy, khalkotauroi, kolomenskoye, mother's boy, nickel alloy, rory mcilroy, self-destroy, whipping boy, wood's alloy

13 letters:
constantinois, dijon-prenois, helen of troy, james purefoy, mackenzie foy, messenger boy, the kid laroi

14 letters:
albert vanhoye, broth of a boy, frances conroy, traveler's joy

15 letters:
andrey zamkovoy, anya taylor-joy, siegfried & roy

17 letters:
my little old boy, seeyouspacecowboy

18 letters:
bell uh-1 iroquois

19 letters:
capital of illinois, certified lover boy