A list of the top legitimate self-submission sites can be found here:
https://secretactorsociety.com/resources#/casting-websites

Other versions of this question might be:

How can I get hired as an actor?
How do I get cast?
What is the best way to solicit filmmakers?
What does self submission mean?
Can I submit myself for auditions?
Can I use Facebook to get auditions?
Tips on avoiding bad projects?
Is there any way I can find roles without just depending on my manager?
Can I help my agent by finding me own work?
Do you have some avenues I can explore to find my own auditions?
How can I track my own acting jobs?