From a book titled Vernacular Universals and Language Contacts: Evidence from Varieties of English and Beyond, apparently citing this work about epenthesis:
Lombardi (2002), reviewing examples of epenthesis from a wide range of
languages, has argued that glottal stops, as pharyngeals, have the
least marked place of articulation for a consonant and hence are to be
expected as epenthetic consonants (e.g. to break hiatus) “all things
being equal” (2002: 246-7). Coronals, she argues, are “the next best
choice” of epenthetic consonant (Lombardi 2002: 223) and so will
appear when “for some reason constraint conflict results in glottal
stop being impossible” (2002: 223). She continues: “glottal stop has
the least marked place, but conflicting requirements may force the
choice of slightly more marked, but still relatively unmarrked Coronal
… careful analysis shows that interacting facts about position,
inventory, etc. in a given language can explain why the least marked …
is not chosen” (2002: 246-7). English English, as we have seen,
provides some evidence of coronals being used to resolve hiatus—/r/
after non-high vowels, [n] after the indefinite article, but both
contexts are now keenly adopting the glottal stop to replace these
historical artefact coronals, in our London data, in Bedford, as well
as further afield in South Africa and Singapore, for example. Language
and sociocultural contact are wheat seem to unite the locations
undergoing a shift to glottal epenthesis to break hiatus.
The use of /n/ to break hiatus appears, that I know of, not only in the indefinite article in English, but also (and coincidentally) in the Greek negative prefix a-, changing to an- when the main word begins with a vowel (hence aerobic → anaerobic).
There are many examples of epenthesis in another work, though many of them do not refer to hiatus breaking. Notably, it says that /r/ is used to break hiatus in several German dialects in Bavaria.
In some Northern dialects of Italian an epenthetic consonant, either /v/ or /g/, is inserted (irregularly) before empty onsets, usually breaking a hiatus (which in turn often arised from the deletion of a medial consonant somewhere between Vulgar Latin and Romance): L. blada(m) → /bjeva/; L. pauore(m) → /pagyra/; L. uua(m) → /yga/. The medial /v/ in the names of the cities of Padova (Padua) and Genova (Genoa) is another example of this.