NVelocity variables available in scriptlets
Following will be available on the product details page
store customer page Store User Category Product
Bellow is the list available across all store side pages
store customer page Store User Category Product Webpage Link
You can use access other objects using above. For example if you want to get the Orders for current user then $User.Orders will provide you that info etc.
NOTE: Use NVelocity to only control the layout. Don't use it as a programming alternative otherwise it will slow down your pages. If you want to customize some logic etc then better to modify the ConLib controls or create new controls to meet your requirements.