If you are near any airports, the AM VHF airband or aviation band (roughly between 108 and 137 MHz) is standard throughout most developed countries, and within the frequency range of most generic RTL-SDR dongles.
Another possibility is the VHF marine band, where many countries broadcast weather and/or sea conditions constantly or often. Often narrow-band FM. A web search for Canada marine radio turns up many sites, such as: http://www.offshoreblue.com/communications/vhf-ca.php
Your national government's radio licensing agency likely has a band plan for amateur radio use. Many of those amateur bands are in the VHF and higher region, in the range of an RTL-SDR.
Many countries use VHF bands for police and fire dispatch (there are probably online lists for your locale in various search databases); but make sure your country's laws allow reception of such.