ん ("n") is the only modern kana that does not appear in the classical Iroha, as the poem predates the character. (Other than that, the work is a pangram.) In doing research for this single, I learned that ん is occasionally added to the end of the Iroha to "complete" the set, and that got me thinking.
To a non-native speaker of Japanese, ん is a unique exception to the consonant-vowel pairings that govern most other Japanese characters; although there are single-vowel kana, ん denotes a single consonant in what is otherwise a syllabic written language. As a standalone word, ん expresses hesitation or uncertainty, but could also be the sound of humming or pondering, almost exactly like the English "Hmm..."
Despite not quite fitting the "usual" pattern, ん is an equal among the other kana; it's not seen as particularly unusual among the 50 sounds. (Non-native speakers like me notice or invent such patterns because of our own writing systems' frameworks, while failing to notice our own limitations.) Regardless, ん feels exceptional, honored among her peers by getting a whole row to herself on some syllable charts (at the very least, breaking conventional patterns via a わ・を・ん row). To me, ん is neither elite royal nor ordinary salaryman, but rather, the standout, "my-pace" artist who enhances the characters around her while occupying her own distinct place, living just outside the neatly ordered rows of あ・い・う・え・お…
So, I thought I would add a little ん to my own Iroha to remind us to all embrace our own potential んness -- what it means to be different, unique, and, perhaps, beautifully incomplete.