There are roughly 25 shirts in the game that you can't tailor but can buy from Sandy at random. The data on which shirt she's selling on any given day is available in the save file. It would be nice to have an icon similar to Queen of Sauce & Traveling Cart if the following conditions are true:

1. Desert is unlocked or accessible by any method. (e.g. Walk to the Desert, Warp Network, etc)
2. Sandy is open. (SVE closes the business on Saturdays and every 22nd after the CC is done)
3. Sandy is selling one of the 25 uncraftable shirts.
4. You don't own the shirt yet.

The shirt IDs are as follows:

20, 23, 24, 41, 42, 44, 46, 47, 50, 55, 57, 61, 77, 81, 83, 85, 88, 91, 109, 110, 111, 119, 120, 121, 122

Thanks for consideration.