Power Depot

• WOTC Official Reminder Textofficial rules
  Modular — This enters the battlefield with N +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.

• WWizards of the Coast2021-06-18
  Official Ruling
  Yes, this land enters the battlefield with a +1/+1 counter, which does nothing while it's a land. When it's put into the graveyard from the battlefield, you may put its +1/+1 counters onto target artifact creature, no matter what Power Depot's card types are at the time.
• WWizards of the Coast2021-06-18
  Official Ruling
  If Power Depot is a creature and gets enough -1/-1 counters put on it to cause it to go to the graveyard, modular will put a number of +1/+1 counters on the target artifact creature equal to the number of +1/+1 counters on this creature before it left the battlefield.
• WWizards of the Coast2021-06-18
  Official Ruling
  Power Depot is a land, so it can only be played as a land. It cannot be cast as a spell.
• WWizards of the Coast2021-06-18
  Official Ruling
  The mana produced by the last activated ability can't be spent to activate abilities of artifact cards in other zones, such as cycling or unearth costs.

Rulings via Scryfall