The Tweak Settings item in the Server Configuration section of WHM contains a large number of miscellaneous settings that affect both the server itself, and WHM and cPanel operation.
These have options to specify the quantity of accounts to be displayed on a page and to set different features related to parked/add-on domains.
Number of accounts to display per page in list accounts: The display item will allow you to specify how many accounts appear on a single page in the List Accounts section of WHM. The default is 30. The word all will display every account on a single page.
Allow users ...