Well, honey, you've got "hopped" and "popped" - those are the only two six-letter words with double "pp" in them. So, there you have it, short and sweet.
Six letter words starting with N:naggednailednapkinnationnaturenectarnearlyneaterneatlyneededneedleneckednegatenervesnestednestleneuternibblenicelynickelniecesnightsnimbleninetynogginnipplenobodynoodlenormalnoticenotionnovelsnovicenozzlenudgednuggetnursesnumbernurishnuzzlenylons
Some six letter words that end in double letters:accessacrossapogeebamboobefallboo booboohoobungeebypasscaresscoffeecouleecuckoodecreedegreeduressegressembossenrollentreeexcessgoateeharassHawaiilayofflycheemorassmuumuupayoffpeeweepizazzrebuffrecallrecessrefillremissripoffrunoffscrollscruffsetteeshrillsoireesquallstressstrolltarifftattoothrilltoffeetoupeeunlessvoodoo
abbreviationaccumulationaccentuationaggressivelyappreciationappropriatedconnotationsdissatisfieddisassociateexpressivelyinstallation
Motion is all I can think of
Six letter words starting with the letter "T"ThreatThreadTinkerTimingTakingTeamedToppedTriple
Here are some 6 letter words ending with T:absentassentbulletcarrotclientdeportdesertdecentexpertexportexpertforgetfaucetferretfreightgobletheighthornetindentimportimpartjacketknightlatentlariatlocustlatestmalletmarketmagnetmaggotnitwitnonfatorientoccultoffsetoutletoutfitpotentpatentpulpitpocketparentparrotpelletresultresortresentrepentregretrelentsecretscriptsplintsquintsummitsquirtspirittalentunseatvacantvelvetwalletyogurt
There are no English words ending in "-six", let alone six letter words.
All words in the English language must have vowels. Even one letter words like 'a' or 'I'.
Six letter words that end with H:AmbushAttachAweighBanishBleachBlotchBluishBoyishBranchBreachBreathBreechBroachBroochBrunchCaliphChurchClinchClutchCrotchCrouchCrunchCrutchDanishDearthDetachDrenchFamishFetishFinishFlinchFourthFrenchGarishGlitchGrinchGrouchGrowthHaunchHealthHearthImpishKiboshKirschKitschLaunchLavishLengthLoofahLowishMenschModishMopishMulishNewishOnrushOwlishPariahParishPaunchPerishPlinthPloughPolishPreachPunishQuenchRadishRavishRelishRewashScorchScotchSearchSeraphSheathSketchSleighSleuthSlouchSnitchSpeechSplashSquashSquishStarchStenchStitchSwatchSwitchSwooshThatchThoughThrashThrushTrenchTroughTwitchVanishWarmthWealthWhooshWraithWreathWrenchZenith
Six (6) letter words that end with on:actionbaboonbeacon.beckon.bonbonbunionbuttoncannoncanyoncarboncartoncitroncocooncommoncottoncouponcrayondaikon.deacon.dragonepigon.falconflagonfusiongabion.gallongibbon.guidon.hagdon.jargonlagoonlegionlesionlessonlotionmaroonmatronmicronminionmotionmuttonnationneuronnotionoptionpardonparsonpatronpersonphotonpigeon.pistonpoison.potionprisonprotonpythonrationreasonreckonregionribbonsalmonsaloonseasonsermonsiphonsummontendontycoonunisonvisionwantonweapon.won tonzircon
Some six letter words ending in R are:antleranswerbeaverbetterbitterborderbutlerbuttercratercursorcuterfalterfiltergarterhamperhatterhealerheaterhotterjuniorkinderladderlardermurderporterpotter
Some six letter words with OOS in the middle:IgloosKazoosWazoosYahoos