Are you looking CPA Networks for incentive or non-incentive traffic btw? Non-incentive people already told you about them, but about incentive you can message me if you like, and I can help you started of course.
And just one main thing (like others already said), don't start with a lot of networks, pick few and that's it, you don't need to spread your earnings/campaigns that much, and also you will waste your time on registration process, learning about every single one and their platforms, etc.