I am working on a custom page template in my theme and I want to remove all other styles and scripts which are loaded, like default theme style, jQuery & other scripts.
I want to remove all for the template page.
What Theme are you using? Your question is entirely Theme-dependent, so specific answers will requiring knowing what Theme you use. (Also, it would be helpful to know if any of your Plugins are injecting scripts.)
The answer really depends on how those scripts and scripts are called.