Potion clears damage from a Pokémon, letting a player stabilize a beat-up attacker or Benched Pokémon. The earliest wording removed up to 2 damage counters, with the Expedition Base Set and Ruby and Sapphire wordings clarifying how to handle Pokémon that only have 1 counter. Black and White simplified this into a flat heal of 30 damage, a wording that has carried through every era since.
Potion first appeared in Base Set in 1999 with art by Keiji Kinebuchi, who illustrated it through several EX era sets. Shin-ichi Yoshikawa took over art duties for the EX and Diamond and Pearl eras, followed by Ayaka Yoshida in Black and White, 5ban Graphics and Toyste Beach in the XY and Sun and Moon eras, and Ryo Ueda in Sword and Shield; Ayaka Yoshida returned from Scarlet and Violet through the Mega Evolution era's Perfect Order. Trainer kit products across the XY era, including the Noivern, Sylveon, Bisharp, Wigglytuff, Latias, Latios, Pikachu Libre, and Suicune kits, each carried their own Potion reprint.
Potion is named directly after the healing item from the core Pokémon video games, which heals damage. In the Base Set era it was also part of the prototype Trainer Deck A given out at pre-release Pokémon Leagues.
Base Set printing is the card's first appearance, illustrated by Keiji Kinebuchi
Black and White printing introduces the flat 30-damage heal wording that later prints kept
BREAKpoint printing bumped the card to Uncommon rarity
Perfect Order printing carries Potion into the Mega Evolution era
The heal-30-damage wording first appeared in Black and White in 2011, replacing the older damage-counter removal text.
Keiji Kinebuchi illustrated the Base Set Potion and continued on many later reprints.
Yes, it appears as recently as the Mega Evolution era's Perfect Order set.
From Base Set (1999) · 3 printings
Remove up to 2 damage counters from 1 of your Pokémon.
From Expedition Base Set (2002) · 1 printing
Remove 2 damage counters from 1 of your Pokémon (1 if that Pokémon has only 1).
From Ruby & Sapphire (2003) · 14 printings
Remove 2 damage counters from 1 of your Pokémon (remove 1 damage counter if that Pokémon has only 1).
From Black & White (2011) · 27 printings
Heal 30 damage from 1 of your Pokémon.
Potion
Item
First printed in Base Set (1999)
Heal 30 damage from 1 of your Pokémon.