Here is the full list of all 20 FreeCell Solitaire Collection achievements.
Win a game of "Penguin"
Win a game of "Prison"
Win a game of "Stalactites"
Win a game of "ForeCell"
Win a game of "Double FreeCell"
Win a game of "Alternate FreeCell"
Win a game of "FreeCell (Relaxed)"
Win a game of "FreeCell"
Win a game of "Baker's Game"
Win a game of "Baker's Game (Relaxed)"
Win a game of "Bastille"
Win a game of "Double ForeCell"
Win a game of "Double Stalactites"
Win a game of "Eight Off"
Win a game of "Eight Off (Relaxed)"
Win a game of "HardCell"
Win a game of "Milligan Cell"
Win a game of "Seahaven Towers"
Win a game of "Seahaven Towers (Relaxed)"
Win a game of "Wiltshire"