Say I play Jundland Terror at the end of a round. Can I choose to perform any action with the interrupt, such as a move action, or does it have to be one of my special actions with the matching arrow symbol? Similarly for To the Limit, can I use it after performing a double move, or can I only use it after performing one of the special actions available to me on the deployment card or on another command card?

The arrow represents Special Action. You can only use special actions with Jundland Terror (or attack, as the card says). I guess you could play Urgency with Jundland Terror? Or Hit and Run? That would be pretty weird.

To the Limit must be used immediately after a special action. Command card special actions do count, though.

Correct. The ability would say "Action" if it meant any action and not just special actions. Also, if you could perform any action, it would not need to include "perform an attack".

I did not know that thank you i will be employing that shortly.