The words once, twice, thrice describe the number of repetitions in a series of such repetitions or possible repetitions. I have searched several authoritative dictionaries & thesauruses without finding other examples. Does anyone know further single words in this sequence?
There are no more in the sequence, other than (unofficially, for humorous effect, "frice", which I've never even heard used.) Even "thrice" is rarely used (other than somewhat ironically.) Instead, one just says "three times", "four times", etc; or, informally, "for the umpteenth time [clean your room!]" (or such, usually a parent to a teenager).
A list of (some) frequency adverbs can be found here: https://en.wiktionary.org/wiki/Category:English_frequency_adverbs