In the Pro Edition the maximum number of SEMRush keywords is 1,000, in the Agency Edition the maximum number of SEMRush keywords is 10,000. The limit is calculated based on the number of domains using SEMRush in TrafficAnalysis.
Eg. you can create 10 projects with the "SEMRUSH" limit set to 100. If SEMRush returns less than the entered limit, the entered limit is still used for the calculation against the allotted number of keywords. You can customize the number of keywords in your domain settings.