3 letters:
ard

4 letters:
bard, blvd, card, gard, hard, lard, nard, yard

5 letters:
alard, barde, byard, carde, chard, erard, garde, giard, guard, huard, icard, k-svd, mocvd, paard, parde, phard, sarde, scard, shard, suard, tarde, varde, vcard, waard, yarde

6 letters:
asgard, barred, bedard, benard, berard, bevard, bovard, boyard, bozard, busard, buzard, canard, charde, decard, denard, dinard, e-card, eckard, edvard, enlard, fayard, fugard, garard, garred, gerard, girard, godard, homard, hucard, jarred, lazard, legard, marred, mccard, menard, minard, mulard, musard, p-card, parred, picard, regard, renard, retard, revard, ricard, rocard, tabard, tarred, upcard, utgard, waarde, warred, zwaard

7 letters:
-barred, adguard, agobard, aircard, amtgard, archard, barnard, beghard, beguard, belgard, bellard, bernard, berrard, billard, blafard, boilard, bolyard, bombard, bongard, bossard, brocard, bunyard, burnard, charred, chocard, cobarde, cocarde, damgard, deckard, dennard, dewaard, diehard, dillard, discard, eckhard, einhard, enguard, esguard, gabbard, gallard, gaspard, geghard, gelbard, gerhard, gibbard, gillard, gilyard, ginyard, giscard, gnarred, gossard, guerard, hilyard, hopyard, innyard, jarrard, keycard, leotard, mullard, newhard, ni-hard, np-hard, panhard, piccard, pickard, poulard, rennard, rutgard, scarred, sinyard, sparred, starred, suchard, sungard, suscard, unguard

8 letters:
armguard, backyard, bankcard, barnhard, barnyard, blancard, blowhard, boatyard, bombarde, boneyard, borchard, bouchard, bouffard, brancard, brochard, bromyard, brossard, burchard, cashcard, datacard, debarred, deeryard, die hard, dockyard, dooryard, drawcard, dungyard, ekkehard, embarred, en garde, eurocard, farmyard, fauchard, filecard, foreyard, glowbard, grignard, grognard, guichard, guinyard, guiscard, hillyard, hortyard, isengard, isracard, jackyard, jacquard, julliard, junkyard, kailyard, kaleyard, kirkyard, lienhard, maillard, mansarde, marquard, meinhard, melgaard, metacard, meteyard, mouchard, moutarde, mudguard, notecard, on guard, outguard, overcard, pericard, postcard, racecard, railcard, railyard, reinhard, safecard, semihard, shipyard, shurgard, telecard, tiltyard, timecard, tonocard, unbarred, valeyard, vanguard, vuillard, whinyard, wildcard, willyard, wirecard, woodyard, zinecard

9 letters:
adenocard, appleyard, arm guard, bank card, bestarred, blow-hard, bodyguard, boucharde, bouffarde, boulevard, brickyard, broussard, cabochard, chauffard, chouinard, colombard, costarred, couillard, coulthard, courtyard, dai-guard, disbarred, disregard, engelhard, face card, fireguard, fishguard, flashcard, graveyard, greencard, grossbard, hildegard, hole card, hypercard, instarred, langobard, leaf lard, lifeguard, longobard, main yard, metrocard, microcard, milliarde, misregard, moneycard, navy yard, newsguard, noseguard, off-guard, off guard, old guard, overgaard, phonecard, pickguard, pockarred, punchcard, rearguard, rock-hard, rope yard, rouillard, safeguard, scorecard, scrapyard, shinguard, show card, side yard, smartcard, stackyard, steelyard, stockyard, studtgard, telengard, tilt-yard, undercard, unscarred, unstarred, videocard, vieillard, waldegard, wasteyard, wild-card, wireguard

10 letters:
afterguard, avantgarde, bank guard, beauregard, bellegarde, blackguard, body-guard, body guard, brouillard, camelopard, campagnard, chainguard, churchyard, co-starred, coastguard, court card, creditcard, crossguard, crowbarred, cubic yard, ddos-guard, door guard, drakengard, drouillard, face guard, false-card, flash card, front yard, green card, hildegarde, keep guard, lettercard, lumberyard, mastercard, montagnard, mouthguard, passegarde, punch card, rear-guard, sauvegarde, schoolyard, scotchgard, shin guard, stableyard, st bernard, switchyard, timberyard, travelcard, trump card, union card, waste-yard, watchguard, yellowcard

11 letters:
avant-garde, avant-guard, avant garde, banlieusard, barclaycard, cattleguard, charge card, charliecard, coast-guard, color guard, credit-card, credit card, crossbarred, easter card, expresscard, fond regard, gaming card, honor guard, ill-starred, molly-guard, paysafecard, postal card, ration card, report card, scratchcard, self-regard, sneezeguard, splashguard, square yard, stack-guard, stand guard, strike hard, swiss chard, watch guard, westergaard, yellow-card

12 letters:
bumper guard, calling card, castle-guard, chicken yard, circuit card, close-barred, colichemarde, compass card, counterguard, daughtercard, drawing card, hlinka guard, leather-hard, library card, mailing-card, penalty card, picture card, playing card, prison guard, punched card, railway yard, splash-guard, trading card, undersparred

13 letters:
advance-guard, alain bernard, baseball card, birthday card, boarding card, business card, finn wolfhard, get-well card, greeting card, identity card, off her guard, off his guard, on your guard, provost guard, saint bernard, scotland yard, sympathy card, tulsi gabbard, visiting card

14 letters:
battle-scarred, christmas card, crossing guard, multimediacard, national guard, naval shipyard, off your guard, on one's guard, security guard

15 letters:
borrower's card, david coulthard, field of regard, jean-luc godard, membership card, no-holds-barred, off one's guard

16 letters:
picture-postcard, picture postcard, praetorian guard, upon one's guard

17 letters:
amazon lumberyard, new scotland yard

19 letters:
yeoman of the guard

21 letters:
live free or die hard

22 letters:
a good day to die hard, the hitman's bodyguard

25 letters:
hitman's wife's bodyguard

4 letters:
bird, byrd, cord, curd, ford, gird, herd, hurd, lord, nerd, ward, word

5 letters:
aired, award, baird, bared, beard, board, bored, cared, chord, cured, dared, eared, fared, fjord, gourd, heard, hoard, horde, laird, lured, mired, njord, sherd, sward, sword, third, weird, wired

6 letters:
aboard, absurd, accord, adored, afford, begird, burred, feared, flared, furred, geared, gourde, haired, inured, paired, poured, record, reward, reword, roared, scared, scored, shared, soared, spared, stared, stored, toured, toward

7 letters:
afeared, assured, attired, blurred, chaired, cheered, cleared, endured, expired, floored, ignored, insured, matured, retired, revered, secured, sheared, slurred, smeared, spurred, squared, stirred, there'd, unaired, uncured, unheard, where'd

8 letters:
ant bird, appeared, compared, declared, deferred, deterred, explored, get word, go board, impaired, incurred, interred, key word, obscured, occurred, prepared, referred, repaired, required, restored, sea bird, ungeared, unmarred, unpaired, unshared, untoward

9 letters:
baby bird, bean curd, besmeared, big board, conferred, disaccord, dog-eared, game bird, good word, head word, in accord, longbeard, myna bird, one-third, overheard, pioneered, preferred, prerecord, rag gourd, rare bird, reassured, ride herd, root word, sash cord, send word, unattired, uncleared, undergird, uninsured, unsecured, unsheared

10 letters:
blackbeard, curse word, dart board, engineered, entry word, ghost word, goatsbeard, henry ford, interfered, night bird, phone cord, power cord, press lord, queer bird, salt-cured, satin bird, scrub bird, sedge bird, shore bird, smear word, sour gourd, undeclared, undeterred, unexplored, unimpaired, unprepared, unrepaired, unrestored, vocal cord, water bird, widow bird, young bird

11 letters:
back-geared, be restored, bread board, bungee cord, canary bird, crown beard, disappeared, draft board, feudal lord, floor board, flying bird, gerald ford, indigo bird, myrtle bird, phoebe bird, quick-eared, sharp-eared, smoke-cured, spinal cord, spoken word, tape record, transferred, tropic bird, tyrant bird, underscored, volunteered, wading bird, weasel word

12 letters:
appeal board, aquatic bird, baffle board, beaver board, bedford cord, binder board, bottle gourd, common chord, content word, diving board, frigate bird, gallows bird, golden horde, gypsum board, ledger board, light-haired, lion's beard, memory board, mother board, notice board, oceanic bird, pelagic bird, school board, self-assured, shovel board, sponge gourd, twenty-third, world record, written word, zoning board

13 letters:
adjutant bird, appeals board, buffalo gourd, butcher board, cavalry sword, circuit board, control board, council board, cutting board, display board, double-geared, drawing board, electric cord, elephant bird, fencing sword, function word, hospital ward, ironing board, opposite word, prairie gourd, rifleman bird, running board, seventh chord, umbrella bird, word for word, writing board

14 letters:
advisory board, baltimore bird, bulletin board, chopping board, cribbage board, crocodile bird, drafting board, draining board, expense record, extension cord, gerald r. ford, imperial beard, medical record, missouri gourd, monopoly board, particle board, planning board, policeman bird, raptorial bird, sandwich board, secretary bird, shoulder board, skirting board, sounding board, strike a chord, telephone cord, throwing board, umbilical cord, written record

15 letters:
criminal record, equivalent word, flightless bird, governing board, jupiter's beard, main entry word, old man's beard, stock of record

16 letters:
backgammon board, corrugated board, graphical record, hearing-impaired, subordinate word

17 letters:
composition board, historical record, phonograph record, visually impaired

18 letters:
golden crown beard

19 letters:
coastal diving bird, gerald rudolph ford

20 letters:
chronological record, congressional record, epiphany of our lord

21 letters:
ascension of the lord, chairman of the board, federal reserve board, stockholder of record, theater of the absurd

25 letters:
electronic bulletin board