theme development – Can I create plugins?

I develop my own WordPress theme that I will use for several clients. It has a Theme Options page so I can easily customize the site each time, but I will also use plugins on every website I create (like an SEO plugin, security, …).

Is there a way to make them "mandatory" so that I get a list of these plugins so I do not have to go to the plugins directory when I install the theme on a new website?