Mask of Mists

Missable.

There are 4 types of Potions you can create, 2 of which are required for story progression. The other two are optional but still beneficial to use. They are as follows:

• Anti-Rust Potion: Required for story progression. Located in the bedroom of the hidden library in the first house you enter at the beginning of the game.
   
• Explosive Potion: Required for story progression. While making your way through the second Dungeon, you'll need to exit out a side entrance/exit before you can complete it (so you can make an anti-rust potion). When you exit out, there will be a set of ruins immediately on the left. Inside a chest within the ruins will be the recipe.
   
• Health Potion: Not required and highly missable. Located on the Fort Terrace (second floor of the first house you enter when you start the game. Requires the Fort Terrace key which is required for Lost and Found).
   
• Breathing Potion: Not required but highly beneficial for the final dungeon. After you complete the puzzle with the 4 Shields/Crests, you’ll come to another gate/house (just to the left of a Graveyard). The recipe is inside a chest in the left room, inside the house. This potion increases the time that you can spend within the pink poisonous areas so it's highly recommended you create at least two before you enter the final dungeon.

Again, out of the 4 of these, the Health Potion is by far the most missable as there are a lot of Health Potions in chests that you can pickup, making it possible that you might not even feel the need to craft any. Make sure you create at least one, though, whether you need it or not.