Niagara Falls—Niagara-on-the-Lake is another close LPC-CPC race that could use any help from non-LPC voters. It used to be a CPC seat.
This page shows a nice visualization of the closest races.
The best thing you can do is advocate for a change to a different system. Instant Runoff Voting would be the bare minimum. Proportional systems like MMP are even better.