Open Work permits:

Post-Graduation Work permit (PGWP)
Spouse of International Student studying in Canada
Spouse of valid Work permit holders in Canada Class
Bridging Open work permits

With open work permit applicant can work with any employer in Canada (Some conditions apply)

Employer Specific Work permits

LMIA Based work permits
Job offer based work permits
Employer specific Work permits

Employer Specific work permit allows workers to work inside Canada for specific employer only with conditions like location of employment, number of hours, wages, etc.

International Experience Canada (IEC)

Three Categories:

1. Working Holiday
2. Young Professionals
3. International Co-Op

Canada has agreement with some countries and citizens of these countries can apply for work permit. These work permits have some restrictions for Applicants depending on their country of citizenship like age, validity, or certain other conditions.

List of countries Whose Citizens can apply under IEC Category: Australia, Austria, Belgium, Chile, Costa Rica, Croatia, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hong Kong, Ireland, Italy, Japan, Latvia, Lithuania, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, San Marino, Slovenia, South Korea, Spain, Sweden, Switzerland, Taiwan, Ukraine, United Kingdom.

For more detailed and up to date information, you can visit Official website of Government of Canada.