Tale's End

• WWizards of the Coast2019-07-12
  Official Ruling
  Triggered abilities use the word "when," "whenever," or "at." They're often written as "[Trigger condition], [effect]." Some keyword abilities are triggered abilities and will have "when," "whenever," or "at" in their reminder text.
• WWizards of the Coast2019-07-12
  Official Ruling
  Tale's End can't target an activated or triggered mana ability. An activated mana ability is one that could add mana as it resolves, doesn't have a target, and isn't a loyalty ability. A triggered mana ability is one that could add mana as it resolves and triggers on an activated mana ability.
• WWizards of the Coast2019-07-12
  Official Ruling
  If you counter a delayed triggered ability that triggered at the beginning of the "next" occurrence of a specified step or phase, that ability won't trigger again the following time that step or phase occurs.
• WWizards of the Coast2019-07-12
  Official Ruling
  Activated abilities are written in the form "[Cost]: [Effect]." Some keyword abilities (such as equip) are activated abilities and will have colons in their reminder texts, if applicable.
• WWizards of the Coast2019-07-12
  Official Ruling
  Abilities that create replacement effects, such as a permanent entering the battlefield tapped or with counters on it, can't be targeted. Abilities that apply "as [this creature] enters the battlefield" are also replacement effects and can't be targeted.

Rulings via Scryfall