Lone Revenant

• WOTC Official Reminder Textofficial rules
  Hexproof — This permanent can't be the target of spells or abilities your opponents control.

• WWizards of the Coast2012-05-01
  Official Ruling
  If you control no creatures when Lone Revenant’s ability resolves, you’ll still look at the top four cards and put one into your hand.
• WWizards of the Coast2012-05-01
  Official Ruling
  If you control Lone Revenant and any other creature (including another Lone Revenant), its ability won’t trigger.
• WWizards of the Coast2012-05-01
  Official Ruling
  Check whether Lone Revenant’s ability triggers after combat damage is dealt but before any creatures that are destroyed due to combat damage leave the battlefield. For example, if you control Lone Revenant and another creature, and that other creature takes lethal damage in the same combat damage step that Lone Revenant deals damage to a player, Lone Revenant’s ability won’t trigger.
• WWizards of the Coast2012-05-01
  Official Ruling
  You must put one of the cards into your hand, even if you’d rather put all four on the bottom of your library.

Rulings via Scryfall