Ok,since you mentioned that(and I wondered why don't we distinguish between them and refer them all as "legacy cards") here is everything about "engine cards" of the game (after hard work

I gathered and made very good explanations about them

) :
Legacy "Card":Some cards leave lasting effects on the duel, even though the card that caused the effect may be out of play. When it is possible or necessary for a player to interact with such an effect, that effect is represented by a Legacy Card.
As with other effects, if it is possible to interact with a legacy, the text on the card is yellow. If it is mandatory, the text is orange.
Damage “Card”This card represents potential damage. What that means is that the creature or player to which this card is attached has unresolved damage “assigned” to it. Because the damage is unresolved, it is still possible to use damage prevention and redirection to lessen or eliminate that damage.
All unresolved damage is represented by Damage Cards; thus, these cards are the only legal targets for damage prevention and redirection spells and effects.
After the damage is resolved (during the appropriate damage resolution step) this card disappears and any damage dealt to the creature (assuming it is still in play) is represented on the creature card itself.
Effect “Card”This card represents the result of a card effect. It is for information only; neither player can interact with an Effect Card.
If an effect affects a particular card, the card to which the Effect Card is attached is the one which has been affected by that effect.
A brief reminder of what effect has affected the card is listed on the Effect Card (for effect).
And my very OWN Engine "Card"

:
Hunting “Card”This card is a reminder of exactly what type of creature the
Aswan Jaguar has chosen to hunt.
If the type listed after “Hunting:” matches the creature type of a creature in play, then that creature might be a legal target for
Aswan Jaguar’s effect.
Activation “Card”This card represents a single activation of a particular card effect. (Remember, only permanents have card effects; no spell will ever create an Activation Card.)
Certain card effects can be used more than once during the same spell chain. In a spell chain, it is important to keep track of which effects are used in what order. Therefore, when a player activates such an effect, each separate activation is represented by an Activation Card.
Blocker “Card”This “card” represents a blocker.
In some cases, a single blocking creature is able to block more than one attacking creature. Rather than displaying multiple copies of the blocking creature in the Combat window (which might be confusing), the Duel represents any block after the first with a virtual blocker, the Blocker Card.
Note that, because the Blocker Card is only a representation, not a “real” card, no player can select it as a target for anything. To target the blocking creature, you must find and target the original. However, automatic combat effects (such as the
Thicket Basilisk’s stoning effect) adhere to the original as if it were identical with each of its Blocker Cards.
I am really tired after all this exhausting work.
