The only thing I have learned that is similar is ところ で which I just learned mostly has to do be used when you are going to say something kind of related that *might* upset the other person.
I’m not upsetting anyone!
So in English people are like blah blah blah, blah blah and then someone goes “oh, speaking of blah blah, blah blah (related topic).”
That was a terrible example. Let me give a better one.
**Man 1:** “so, our dishwasher was broken and needed to be fixed.”
**Man 2**: “oh man, dishwasher maintenance is costly!”
**Man 1**: “seriously”
**Man 2**: “**Speaking of dishwasher repair**, I dropped a plate *in* the dishwasher the other day so…”
5 comments
Xと言えば might be the grammar pattern you’re looking for
因みに (ちなみに) might be similar to what you’re searching for.
そういえば is like “Now that you mention that”, “that reminds me” or “speaking of which”
This might be helpful: https://ja.hinative.com/questions/72174
a simple
Xなら
for “speaking of X” works just fine, too