Surrvogel

Fliegend
Immer wenn der Surrvogel einem Spieler Kampfschaden zufügt, führe Wucherung durch. (Bestimme eine beliebige Anzahl an bleibenden Karten und/oder Spielern und gib ihnen dann von jeder Sorte Marke, die dort bereits liegt, eine weitere Marke.)

Colipervier

Vol
À chaque fois que le Colipervier inflige des blessures de combat à un joueur, proliférez. (Choisissez n'importe quel nombre de permanents et/ou de joueurs, puis donnez-leur à chacun un autre marqueur de chaque sorte déjà présente.)

かき鳴らし鳥

飛行
かき鳴らし鳥がプレイヤー１人に戦闘ダメージを与えるたび、増殖を行う。（望む数のパーマネントやプレイヤーを選び、その後、すでにそこにあるカウンター１種類につき、そのカウンター１個を与える。）

Thrummingbird

Flying
Whenever this creature deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Commander Masters

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phyrexia: All Will Be One

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate.

New Capenna Commander

An ability that triggers "Whenever you proliferate" triggers even if you chose no permanents or players while doing so.

If a permanent ever has both +1/+1 counters and -1/-1 counters on it at the same time, they're removed in pairs as a state-based action so that the permanent has only one of those kinds of counters on it.

If a player or permanent has more than one kind of counter on it, and you choose for it to get additional counters, it must get one of each kind of counter it already has. You can't have it get just one kind of counter it already has and not the others.

Players can respond to a spell or ability whose effect includes proliferating. Once that spell or ability starts to resolve, however, and its controller chooses which permanents and players will get new counters, it's too late for anyone to respond.

To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents. You can choose any player who has a counter, including opponents. You can't choose cards in any zone other than the battlefield, even if they have counters on them.

You don't have to choose every permanent or player that has a counter, only the ones you want to add another counter to. Since "any number" includes zero, you don't have to choose any permanents at all, and you don't have to choose any players at all.