Here is the full list of all 31 Fifty Words by POWGI (EU) trophies - there are 5 bronze, 22 silver, 3 gold and 1 platinum.
Collect all the trophies
Find MERCURY 3 times
Reset a completed puzzle
Review a completed puzzle
Complete "Double-O Heaven"
Check the word list with only one word left to find
Find DRIP 3 times
Find BOOTS 3 times
Find DRIZZLE 3 times
Find EAGLE 3 times
Find CHERRY 3 times
Find ZOMBIE 3 times
Complete "Money Money Money"
Find MINT 3 times
Find PARIS 3 times
Complete "Feathered Friends"
Find all the diagonal words in a puzzle first
Complete a puzzle using only one color
Complete "Too Many Cooks"
Complete a puzzle while only highlighting words backwards
Complete "Ends With X"
Find BABY 3 times
Solve a puzzle in less than 3 minutes
Complete "Tee Time"
Complete a puzzle using 10 different colors
Complete a puzzle without looking at the word list
Complete your first puzzle
Complete "Got the Blues?"
Highlight a word backwards
Edit the palette and choose 10 new colors
Zoom out for 5 seconds