Here is the full list of all 51 Gwent: The Witcher Card Game trophies - there are 42 bronze, 5 silver, 3 gold and 1 platinum.
Mill 50 cards.
Equip a vanity leader skin, an avatar, a border and a title
Send "GG" 50 times.
Fully deplete your deck.
Reach level 15
Collect 50 unique cards from 1 faction
Start a round with 10 points on the board.
Destroy a Doomed enemy with a Doomed ally.
Have 4 artifacts in play at any time.
Destroy a unit with Zeal before it's triggered.
Win a round with only Order units.
Use 10 order charges in a single turn.
Win a multiplayer game without Golden cards in your deck.
Destroy a unit that is Immune.
Obtain at least one leader from each faction.
Control at least 5 cards with the same power.
Finish a contract with Gaunter (complete an arena run).
Deal a total of 30 damage to units in one multiplayer game.
Destroy 3 or more units with single card.
Fill your opponent's side of the board with row effects.
Win a round and game, after losing by 20 points.
Have card advantage of 3 cards.
Transmute a card.
Win a multiplayer game by 50 or more points.
Boost unit to over a 30 points in a multiplayer game.
Get a draw in a multiplayer game.
Have a winstreak of 3 in any multiplayer game mode.
Win a Regular Battle without redrawing any cards.
Win a battle without killing any of the opponent's units.
Win a game with 2 cards remaining in hand.
Play a maximum number of units into any single row.
Finish 3 online matches
Spawn five allies in a single turn.
Order 3 units in a single turn.
Play one arena game.
Play a card from 5 different factions during a match.
Play one ranked game.
Destroy a Legendary enemy with a Common ally.
Play a bronze and a gold card in a multiplayer game.
Complete the basic tutorial.
Get all trophies.
Smash 100 kegs.
Reach level 40
Reach Prestige 1.
Reach Rank 20
Own at least 150 premium cards
Play 5 cards in single turn.
Have 3 copies of the same card in an arena deck.
Win a game using 15 special cards.
Resurrect at least 5 cards in a match.
Complete an arena run with at least 6 wins.