Each and every company follows their own format for testcases. But the final aim is to cover all the functionality to test the project.

A Good 'Testcase'  is has not morethan steps and cover more functionality in the single shot.

TestCases for 'Winrunner' is prepared in terms of script. If we record the script then these are nothing but testcases.

 TestCases for 'LoadRunner' is prepared in terms of scenarios and actions.

I don't know 'Client side test cases'.