When you add a new era to your map, depending on what letter you give it`s script, will determine what icon it has in the instant action menu. Of course it can be changed in the addme with this code I`m wondering if anyone has made a list of each of the different icon`s names?
And if no one has, then do any of you people know how I`d get an icon of a blaster rifle?

You need to see about adding a custom shell.lvl to your mod and adding your new texture there, then reference the new texture in that bit of code.

Hint - a custom shell, not a complete stock one.

And the 4 original icons are rep_icon, cis_icon, imp_icon and all_icon