If you’d like to include scripts that get run on boot for Ubuntu Desktop you can use synaptic manager to load BootUp-Manager.
This can be accessed through the >>System >>Administration >>BootUp-Manager menu.
You will be able to select or deselect scripts that are in the /etc/init.d/ folder to run on boot. If you need to something to run that isn’t available in /etc/init.d/ I suppose you’ll have to create your own script. Often when you install a program through apt or by compiling an sample init script will be created which is not copied to the /etc/init.d/ folder so you can search around for a sample init script or Google.
/etc/rc.local is the file to add scripts to run at boot time for Ubuntu Server.