size method can be used in the rendered attribute for conditional rendering based on list size in the Salesforce Visualforce page.

Sample Code:

<apex:pageBlockTable 
     value="{!empList}" 
     var="emp" 
     rendered="{! IF(empList.size > 0, true, false)}">
     <apex:column value="{!emp.Name}"/>
     <apex:column value="{!emp.Age}"/>
</apex:pageBlockTable>

The pageblock will be rendered only if the empList list size from the apex controller is greater than zero.