I saw one a long time ago, but I lost the link. Does anyone happen to know? I appreciate any help!

Restocking has changed many times, so 'long time ago' might not apply now.

Right now, shops stock every six minutes.

I don't recall seeing such a guide, but if it does exist it may be pretty old and things may have changed since.

From personal experience:

• regular shops. The ones I hang out in tend to restock every 5 min or so
• Subeautique. Seems pretty variable to me but a few times an hour.
• Blackheart Hollow: several times a day, extremely random.
• Token shop. After an item is announced in the news, generally every 4 hours, but its done manually so if the staff doing it is busy/sleeping/forgets, could be way off that time frame. When its for a new nostalgic instruction manual, I don't think it restocks at all. For a "Choatic" restock, I've never actually timed it.
• Freyalise Trading Company. Open for a short time in Sept. While open, I think it just restocks like normal shops.
• Migrating Masks. Only open during Masquerade, and restocks like a normal shop during that time.
• Avalanche Emporium. Only open during "winter" season and IIRC it remains fully stocked at all times but there is time limit on buying.