Finvis is a great free scanning tool. I have a stockcharts subscription that I use to scan for stocks in an uptrend that are making new highs.
Always long. Short trades are taxed differently in Canada. In a bear market I'll trade the inverse ETFs
This website has an amazing amount of data available for free. Is the data reliable? In other words, are the IV calculations comparable to those provided by livevol, etc.?
oh man there are a gazillion ways to scan, all depends what you are doing/want to do. What kind of trading to you like to do ? What type of stock moves plays do you want to find ? I use Trade Ideas and can tailor a scan to whatever you are looking for. I mostly daytrade and I have scans for gapping up and down stocks each day and swings, i have scans for momo stocks, i have scans for stocks making super crazy moves, I have scans for just IPO's, scans for beaten down stocks that have shown reversal. scans for halted stocks. It is endless. But tradeideas is super powerful for whatever you need.