The most common types of intermediaries are agent, contractor, joint venture, and co-operative participant.  Here is further information on each of them.

In CRA’s Guidance “Using an Intermediary to Carry out a Charity’s Activities within Canada” it notes:

4.1. What are the most common types of intermediaries?
Following are descriptions, provided for the purposes of this guidance only, of the four most common types of intermediaries a charity might use to carry out its own activities.
The type of intermediary that a charity needs to carry out an activity will depend on the facts of any given situation. The CRA does not recommend using one type of intermediary over another.

4.2. Agents
An agent is an intermediary that agrees to carry out specific activities on a charity’s behalf. A charity often uses an agent when the charity cannot send its staff to a region to carry out an activity.
Example
A charity is registered to provide psychological counselling services to people in under-served northern communities across Canada. None of the charity’s staff has any training in providing counselling. Instead, the charity locates a number of professional psychological counsellors with their own independent practices who agree to act as the charity’s agents in carrying out the activity.
The charity and the counsellors create and sign an agreement describing the details of the activity and their respective roles and responsibilities. The agreement states that the charity will pay all travel and operating expenses, and the counsellors will volunteer their time and make typical day-to-day operating decisions, such as renting offices, notifying the communities of their services, and hiring local support staff.
The counsellors provide regular, detailed reports on the use of the charity’s resources, according to the terms of the agreement. The charity intervenes as required to provide ongoing instructions on the use of its resources to make sure that the activity continues to be carried out according to the agreement, and that the activity is achieving the charity’s own charitable purpose.
Registered charities should consider how they structure agency arrangements, since the existence of an agency relationship may expose them to significant liability for the acts of their agents. Even if there is no formal agency agreement in place, a court can attach liability to a registered charity if the court decides from the circumstances that an implied agency relationship exists.

4.3. Joint venture participant
A joint venture participant is an organization that a charity works with to carry out a charitable activity. The charity and one or more joint venture participants pool their resources to accomplish their goal under the terms of a joint venture agreement.
A joint venture participant differs from an agent in that the charity is not relying entirely on the joint venture participant to carry out activities for the charity. Instead, the charity works with a joint venture participant to further the charitable activity.
Typically the charity has members sit on the governing board for the entire project, letting the charity make decisions on the use of its resources for the project. The structure of a joint venture varies from case to case.
A charity must be able to establish that its share of authority and responsibility over a venture allows the charity to dictate and account for how its resources are used. If a charity does not have enough decision-making authority to make sure that its resources are used as it directs, it may have difficulty establishing that it is carrying on its own activities.
Example
A charity is registered to relieve poverty by providing small business loans in an economically challenged community. The charity collaborates with a for-profit bank to design an activity that will provide entrepreneurial training, support services, and start-up loans to hard-to-employ people.
The charity and the bank form a governing body to operate the venture. The charity provides roughly 40% of the funding for the project and its representation on the venture’s governing body is approximately 40% of the decision-making power. As long as the venture only uses the charity’s resources for the charity’s own activities, the arrangement should be acceptable.
However, with only 40% of the decision making power, it is possible the bank could decide to use the charity’s resources inappropriately, such as carrying on different activities that are not those initially agreed to. Therefore, the arrangement should include a provision that allows the charity to discontinue devoting its resources to the venture under such circumstances.
The CRA will look at any venture as a whole, and a charity’s participation in a venture, to make sure that the charity’s resources are only furthering its charitable purposes. If the purpose of an overall project is not charitable, such as providing excessive or undue private benefit to an individual or company, a charity’s own activities on behalf of that project may not be acceptable, even if those activities would normally be considered to be furthering its charitable purposes if carried out on their own.
For a list of the factors the CRA looks at when examining joint venture arrangements, see Appendix B.

4.4. Co-operative participants
A co-operative participant is an organization that a charity works side by side with to complete a charitable activity. Rather than pooling their resources and sharing responsibility for the project as a whole, as in a joint venture, the charity and other organization(s) instead each take on responsibility only for parts of the project.
Example
A charity and a non-profit corporation have a common object to assist youth at risk in a major city. The charity specializes in helping teens recover from substance abuse. The non-profit provides academic assistance to teens with learning disabilities. They decide to lease a space jointly to run a new program, aimed at helping youth at risk complete high school.
Each organization operates its particular program out of its half of the leased space, using its own staff and resources. While they co-operate by, for example, sharing information and recommending potential candidates for each other’s programs, each organization retains ownership of its assets and carries out its responsibilities independently, without oversight or control from the other body.

4.5. Contractors
A contractor is an organization or individual that a charity hires to provide goods and/or services. For example, a charity might hire a for-profit construction company to build temporary housing for homeless individuals.
A contractor is an intermediary with whom direction and control is usually exercised through the terms and oversight of the contract between the charity and the person or business providing the goods or services.
Example
A charity is registered to carry out research into a particular disease. As part of its activities, it contracts with a private medical laboratory to test new compounds for their disease fighting properties.
The charity and the laboratory draft and sign a contract that outlines all the terms and conditions of their relationship. The contract is the instrument through which the charity directs and controls the use of its resources, monitors the use of its resources as the laboratory carries out the activity, and ensures that only fair market value is paid for any work done.

For more information on the CRA Guidance “Using an Intermediary to Carry out a Charity’s Activities within Canada” (Reference number CG-004) see:
https://www.canadiancharitylaw.ca/index.php/blog/category/using_intermediaries_in_canada/ or
http://www.cra-arc.gc.ca/chrts-gvng/chrts/plcy/cgd/ntrmdry-eng.html