Unfortunately there are no private sponsors here.
You can try reaching out to organizations on the Sponsorship Agreement Holder list on this site. Note that many / most of these organizations are no longer accepting new sponsorship agreements.
https://www.canada.ca/en/immigratio...p-program/agreement-holders/holders-list.html
If you have family or friends in Canada, you can also see if they can get a group of people together for the Group of 5 sponsorship process. However to qualify for this process, you would first need to be officially recognized as refugees by UNHCR - which requires you to leave Serbia and move to another country. You cannot be recognize as a refugee from within your home country.