AdThrive only accepts sites that have had at least 100.000 unique visitors in the last thirty days. The sites accepted by Adthrive have large to very large traffic volumes.
Ezoic does not have exact specifications regarding the required traffic of a website. Every publisher can apply here.
Mediavine only accepts sites that have had at least 50.000 unique visitors in the last thirty days. The pages accepted by Mediavine are of medium size in terms of traffic.
Monumetric expects at least 10.000 monthly unique visitors. Especially small to medium-sized websites are found here in terms of traffic.