You cast Azorius Herald, which has When this creature enters, you gain 4 life. Youll gain 2 life, putting your life total back up to its maximum of 10
Merry & Pippin are the best choice if you want to focus on the Food + Token aspect of the deck, as Pippin provides the Food that Merry needs to feed your growing army of creature tokens and then Pippin turns that into a hasty finisher
This is unlike loyalty counters on planeswalkers, which add to the owners total life pool instead
These appear to be Ravensburger exclusives, available through Ravensburger stores, their online shop, and expos where Ravensburger attends, though this hasnt been officially confirmed yet
While you can't play more than a handful of games of Commander without stumbling upon numerous +1/+1 counter synergies and decks, -1/-1 counter decks are few and far between