List of spirits (complete list)
All fighter spirits (except for those unlocked by challenges) can be acquired by finishing Classic Mode with that particular character and also by purchasing them through the Vault's Shop for 300 coins. Any spirits that appear in the Spirit Board but also have a different method of obtaining (bought at a Shop, Challenges, and Summons) will not appear on the Spirit Board until unlocked by the alternate way. However, this doesn't apply to any Enhanced Spirit.
List of Spirits