A lot of abilities in Savage RIFTS are listed as using a Free Action to activate, for example:

• The Cyber-Knight’s Cyber-Armor, Psi-Sword, and Psi-Shield
• The Mystic’s Cosmic Confluence ability
• “Innate” abilities in general
• The Crazy’s “Losing It” ability
• Powering up a TW device
• Switching modes on various gear and weapons
• Siphoning PPE from allies
• The Exalted Manipulation Mega Power Modifier to elemental manipulation (the fact that it can be used only once per round pegs it as limited free action right there)
• Attacking with the Deadly Illusion Mega Power Modifier
• Shaking off the effects of various powers such as blind or puppet, or seeing through a power such as disguise or illusion
• Various uses of innate powers such as the Nega-Psychic’s Disrupt Magic ability
• Use of various Edges such as Fast Draw

Now, in SWADE 5.0, there are only two Limited Free Actions mentioned, Change Position in a Chase, and moving a target using telekinesis, so my instinct when it comes to Free Actions in Savage RIFTS is just leave it at that. Similarly, the only Limited Action I’m seeing in SWADE that has any bearing on Savage RIFTS would be in using elemental manipulation to “Move” an element.