Pennon Blade — ruling 1

As long as you control Pennon Blade, its ability constantly counts the number of creatures you control. It doesn't matter who controls the creature it's equipping (in case an opponent somehow manages to take control of that creature). If you control the creature it's equipping, the bonus will include that creature too.

Pennon Blade : règles, fonctionnement et interactions (MTG)

Pennon Blade is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Equipped creature gets +1/+1 for each creature you control. Equip (: Attach to target creature you control. Equip only as a sorcery.)

How it works : Pennon Blade

Original English text — Wizards of the Coast / Scryfall

#1June 15, 2010· Wizards of the Coast
As long as you control Pennon Blade, its ability constantly counts the number of creatures you control. It doesn't matter who controls the creature it's equipping (in case an opponent somehow manages to take control of that creature). If you control the creature it's equipping, the bonus will include that creature too.
No other card is named in this ruling.