There are none. There might be some starting with ex, but a collective noun that starts with x doesn't exist.
Collective nouns are an informal part of language. Any noun that suits the context can function as a collective noun; for example, a xenophobia of foreigners or a Xanax of xenophobes.
Xavier
All proper nouns start with a capital letter.
A common noun is a general word for any person, place, or thing.Examples of common nouns that start with the letter "u" are:ukuleleudderulcerumbrellauncleunderstandingunitunityurgeuseuserutopia
Some common nouns that start with 'i' are:ibexibisiceiconideaidentityidolimaginationimpinchinformationinkinninsightinspirationinventioninundationionirisironironyislandisolationissueisthmusitem
Some abstract nouns that start with E are:easeeducationelementeminenceemotionempireenigmaerrorexcellenceexcitementexcuseexercise
Examples of nouns that start with 'x' are:xenonxenophobiax-rayxylemxylophone
Some nouns that start with X are:Xenia, OHXenon.xerographyx-raysxylophonexylemxylene
Some nouns that include the letter X are:anxietyaxaxiomboxexitfoxx-rayxantusxenophobiaxenopsXeroxxylophone
Common nouns that start with the letter T include:tabtablettapetaxteateetelevisiontracertracktrackertriangletricktrickstertriketrinkettripletstubtubatuna
Some nouns starting with the letter A:aardvarkabilityactorAdamaerosolaffairagateairalarmAmericaanchorapple
Concrete nouns that start with X are:xylophonex-ray machinex-ray fishXerox copy
Some nouns that end with the letter X are:annexanthraxapexboxclimaxcortexcruxduplexequinoxfaxfixflaxfoxhelixhexhoaxibexindexjinxlarynxlatexloxlynxmixonyxoryxoxparadoxpoxsaxsexsixtaxvortexwaxXanaxXerox
Examples of nouns that start with K and S are:kangarooKarenkayakkelpKentuckyketchupkindnesskingkitchenkneeknowledgekoalasadnesssaladsealshirtsilksinkskysorrowSpamstarswordspy
Some common nouns that start with 'i' are:ibexibisiceiconideaidentityidolimaginationimpinchinformationinkinninsightinspirationinventioninundationionirisironironyislandisolationissueisthmusitem
Some nouns that start with the letter 'I' are:ibisiceice creamice rinkice skatesicebergIcelandicicleicingiconideaidealidentificationidentityidiomidiotidoliglooignoranceiguanaIllinoisillnessillusionimageimaginationimbecileimmigrantimmortalityimmunityimpimprovementimprovisationincenseinchinclinationincreaseincubusindependenceIndiaIndianaindifferenceindividualindividualityindustryinequityinfamyinfantinfantryinfectioninferenceinfidelinflammationinformantinformationinfusioninitialsinitiativeinjuryinkinklinginletinmateinninquiryinroadinsanityinsectinsertinsertioninspectioninstanceinstantinsulationintelligenceintentinternInternetinterpretationinterventioninterviewintestinesintonationintroductionintuitioninvasionionionsiotaIowaireIrelandiridescenceirisironironyirradiationirregularityirrelevancyirrigationirritantirritationislandisleIsle of ManisolationisotopeissueisthmusItalyitchitemivoryivy
Some nouns for things that start with the letter A are:acornanchorankleappleargumentazaleaSome nouns for places that start with the letter A are: AfricaAnnapolisArabian DesertArizonaArctic CircleAustralia
Common nouns that start with the letter y:yardstickyarnyearbookyo-yoyogurt