First I want to tell that I've read this answer. Main menu has gone now... Well perfect would be to have a list of all applications and select among them.
I think the idea is that new apps should ask to be added to the list of startup applications if that is deemed useful. Evolution alarm notification, for instance, seems to do that. Alacarte is a desktop-file manager. It isn't really related to the menus at all. If you add an entry to it, it'll appear in Unity dash as well. Anyway, adding startup applications is easier than it was in the old days:
Main Menu is actually not directly related here, but you can still install it via:
sudo apt-get install alacarte
For adding applications to autostart you can use Startup Applications. Of course there is not a ready list for that, you should know the name of the application, more accurate "the starting command" of the application.
If you don't want to use Main Menu try TAB on command line.
a_few_letter_of_name_of_application TAB TAB
You can learn the command like that.
Another way learning the command is this one:
dpkg -L package_file_name
and look for the /usr/bin entry.
package_file_name is the name from package_file_name.deb