Most of these items are usable by Any Class, so I only noted the one(s) that is not.
Please let me know if you spot any errors.
Act 2:
Family Quest rewards. You can buy only one type of item, but you can buy it in multiples. 500gold/bottle. Go back to the family you did the quest for in Chapter 11 (you can do it immediately after the quest or on your last free day).
Spoiler:
Rowinda's Candy. Reduces any neg. physical condition by 1 and heals 25% of total HP and SP (for a single character).
Spoiler:
Act 3:
Flowervale Honey: Completely restores HP/SP for one character.
Spoiler:
Act 4:
You can make more Rowinda's candy:
Spoiler:
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