Here is the full list of all 12 Letter Quest Remastered trophies - there are 7 bronze, 4 silver and 1 gold.
Spell 3000 words
Complete 50 quests
Earn 40 crystal stars
Earn 120 yellow stars
Do 100 critical attacks
Spell 3 words with no vowels
Purchase 50 merchant items in battle
Defeat 250 monsters
Purchase 30 upgrades
Open 10 treasure chests
Use 25 plague tiles
Finish a stage with full health