Here is the full list of all 13 Lexica achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Complete all 288 Puzzles
Complete all medium Puzzles
Complete 192 Puzzles
Complete all hard Puzzles
Complete 15 Puzzle Packs
Complete 96 Puzzles
Complete all easy Puzzles
Complete 5 Puzzle Packs
Complete 48 Puzzles
Complete 24 Puzzles
Complete 12 Puzzles
Complete a Puzzle Pack
Complete your first Puzzle