そういえば

Come to think of it, I have a feeling I’ve heard such a story before.

Come to think of it, I've never been on a family trip.

Now that you mention it, I feel like I did say something like that.

Come to think of it, I've heard about that.

Now that you mention it, that was indeed the case.

Come to think of it, I still hadn’t told you my name.

Now that you mention it, I wonder what everyone is doing?

Come to think of it, I have a feeling we talked about something like that last summer.