Here is the full list of all 47 Knowledge is Power trophies - there are 35 bronze, 9 silver, 2 gold and 1 platinum.
Obtain all trophies
Play thirty games
Win three games as the Hotdog Man character
Win a game with each character
Win three games as the Fairy character
Win three games as the Spaceman character
Play fifteen games
Win three games as the Mountaineer character
Win three games as the Magician character
Win three games as the Cowgirl character
Use a Power Pick twenty times
Win three games as the Scientist character
Complete a Two-player game
Play five games
Answer all multiple-choice questions in a single game correctly with all players
Complete a Three-player game
Win three games as the Duchess character
Get the correct answer to a Finale question after trying all the wrong ones
Use a Power Pick on a door choice, play Points Party and then be the only player to get the question wrong
Get 100% correct answers on a Sorting question
Choose the same incorrect answer to a multiple-choice question with all players in a 3-6 player game
Complete a Four-player game
Finish a 3-6 player game with all players within four steps of each other
Freeze six opponents as the Cowgirl character
Everyone Freezes everyone else on a question in a 3-6 player game
Complete a Five-player game
Come from last in the Finale to win a 3-6 player game
Answer first and correctly after being hit by two Nibblers in the same question
Place a Bet on a player that answers correctly first, but get the wrong answer yourself
When Bombled, tap two Bombles on your answer screen
When Frozen, remove ALL the Ice from your answer screen
Answer first but be the only player to get a multiple-choice question wrong in a 3-6 player game
Get 100% correct answers on a Linking question
Be the only person to miss out on a Points Party
Apply three or more Freeze Power Plays to one player on the same question
Use all of the game's characters
Complete a Six-player game
When Glooped, remove ALL the Gloop from your answer screen
Everyone Power Plays everyone else on a question in a 3-6 player game
Play five Power Plays on one character on the same question
Play every Power Play with the same player in a single game
Choose an incorrect answer to a multiple-choice question with only one player in a 3-6 player game when all other players get it right
Play a Power Pick with every player in a single game
Apply three or more Gloop Power Plays to one player on the same question
Power Pick a door when everyone else chose a different door in a 3-6 player game
Answer first and correctly after being hit by a Gloop, Freeze and Bomble in the same question
Choose all four doors, with at least one character on each door, in the door choice screen