What are all the triggers in Riftbound that you can play reactions to, and for which triggers can you play an action spell to start a chain?

Ruling: Triggered abilities can be recognized by the word "when" followed by a game action or event, the word "at" followed by a point in time during the turn sequence, or the phrase "the [Nth] time" followed by a game action or event. You cannot play Action spells in response to triggers because triggers go on or start a chain and Actions cannot be played in a closed state.

Nuances:

• Activated abilities (those requiring exhausting or paying costs) are abilities, not triggers
• "Do this" effects create reflexive triggers
• When a trigger says "when you play me, I deal 1 damage" and the card is removed before resolution, it can't deal the damage because it's no longer on the field
• When a trigger says "play a 1 [M] recruit to your base", that should still resolve even if the source is removed