[b]Solar, Arc, and Void.[/b]
[url=http://imgur.com/4fJMbeJ]The Elements[/url]
[u][b]SOLAR[/b][/u]
The Thrall wizards have been spotted using the solar type orange colored over-shield that can be taken down using the solar type element weapons.
[url=http://imgur.com/AHFEvy7]Thrall Wizard's over-shield[/url]
[u][b]ARC[/b][/u]
The Fallen captains you find use a blue colored over-shield that can be taken down using the arc type element weapons.
[url=http://imgur.com/0COYGuq]Fallen Captain's over-shield[/url]
[u][b]VOID[/b][/u]
The Vex minotaurs have a purple colored over-shield that can be taken down using the void type element weapons.
[url=http://imgur.com/OGZ59D2]Vex Minotaur's over-shield[/url]
The big take away here is that element energy on weapons only has an effect on over-shields that match that element.