Since ぢ in spellings was merged into じ in modern kana usage, じや/ぢや, じゆ/ぢゆ, and じよ/ぢよ were merged into じゃ, じゅ, and じょ.
That made me wonder, what about ぢゃ/ぢゅ/ぢょ? They exist, and I found them present in gojuuon hiragana/katakana charts geared at Japanese kids (referred to by the charts as あいうえお ひょう)
I can't think of any rendaku words that start with ちゃ/ちゅ/ちょ - if anything these sounds invoke a strong Chinese feeling and on'yomi comes to mind immediately.
When I type dya/dyu/dyo, and I hit the 変換 key on my keyboard, the only thing that shows up are the katakana and halfwidth/fullwidth roman variants of what I typed.
Does anyone know if these kana, ぢゃ/ぢゅ/ぢょ (ヂャ/ヂュ/ヂョ) are used in modern kana usage?