Awesome.
On the Canadian end, the BMO low volatility Canadian ETF is one I'm finalizing a report on right now and should be done in a few days. It's a beta (volatility) fund that has provided relatively strong returns in the past.
If you're looking to hold a core portfolio of stocks with some ETFs you do need to be aware of overlap.
On the more passive/moderate risk side of things, you'd probably want to avoid sector specific ETFs. Think retail ETFs, semiconductor ETFs. They post more volatility and are a bit more concentrated.
Look into ZUQ (we have a report in our ETF section) and ZLB (I should have a report done in the next few days). These funds can potentially compliment a portfolio of individual stocks.