Doubled LeTTers, Sometimes SOOthing, Sometimes MiSSing

While paTTing a puRRing cat, TO's Significant Other (TOSO) wondered whether other words bearing adjacent doubled leTTers were more likely than most to have sOOthing characteristics. This led TO to ponder how much of the alphabet could be speLLed with English words that doubled particular leTTers in question. Representatives for the foLLowing sixtEEn leTTers came to mind in fairly short order, some sOOthing and others not: AArdvark, eBB, aCCuse, eDDy, bEE, eFFort, eGG, teLL, coMMit, coNNect, pOOl, oPPosite, eRR, leSS, aTTend, and buZZ. (Besides Q, the gaps are concentrated: H-K and U-Y. Coincidence?) If you identify candidates for the miSSing leTTers, please coMMent. TO may also consider further or check other references, but doing so beforehand sEEmed to spoil the puZZle's chaLLenge.