[Nyororin]

I really find it hard to come up with any sentence I would actually say that ends with だ.

The closest I use regularly is probably そうなんだ or ～だったんだ but even that isn`t all that often, and it certainly isn`t the same usage as です.

だけど,　だね, だよ, だよね are 500 times more common. At least they are in my speech. If I were pressed I`d probably only say I use だ alone when surprised or something... うわ、・・・だ！　Or maybe when talking to myself. これだ！