The List
There are 107 7 letter words with X as the last letter. The highest scoring is FUZZBOX at 37 points in Scrabble. 65 carry three or more vowels, which makes them useful for dumping a vowel-clogged rack.
ABRASAXAIRPROXANTEFIXANTHRAXANTISEXANTITAXAPOPLEXAPTERYXARUSPEXBANDBOXBATEAUXBEATBOXBEESWAXBOOMBOXBOSTRYXBROADAXBUREAUXCADEAUXCARAPAXCASEMIXCASHBOXCELOTEXCHAMOIXCHOENIXCOALBOXCOANNEXCOMPLEXCONFLUXCOTEAUXDEINDEXDISTRIXEDITRIXEQUINOXFAREBOXFEEDBOXFIREBOXFLUMMOXFOWLPOXFUNPLEXFUZZBOXGATEAUXGEARBOXGRAVLAXHELLBOXHOMOSEXHUMIDEXIMPOSEXJAMBEUXJUKEBOXKICKBOXKLEENEXLOCKBOXMAILBOXMILIEUXMINIMAXNARTHEXORATRIXOUTJINXOVERLAXOVERMIXOVERTAXPACKWAXPANCHAXPARADOXPEMPHIXPERPLEXPERSPEXPHALANXPHARYNXPHOENIXPILLBOXPOSTBOXPOSTFIXPOSTTAXPRINCOXREAFFIXREANNEXRECTRIXREINDEXRESEAUXSALPINXSALTBOXSANDBOXSEALWAXSEEDBOXSHOEBOXSHOWBOXSIMPLEXSOAPBOXSONOVOXSPANDEXTALKBOXTECTRIXTELEFAXTELETEXTOOLBOXTORTRIXTREEWAXTRIPLEXTUBIFEXVAUDOUXVICTRIXVITRAUXWOADWAXWOODBOXWOODWAXWORKBOX