There is no software developed to show you what applications or services can be deleted from that list. You will have to analyze them to see what they're doing and then disable or delete them. For services, things tend to complicate themselves that's why it isn't recommended to change their preferences.
For startup items, go to Start > Run > msconfig and switch to Startup tab. You can then see what applications you have set up to start when the computer starts. Disable all that you don't use or know they're not port of the operating system such as sound applications, keyboard and other input devices, etc.