Onnet town General Store
Usually in events they will have special hats or furniture or even items. The store employee npc will usually say that they just got stock, but when even is gone will say that theres no stock and the delivery is running late.
Lava Pet
On 1 July to 9 you can walk into a store room only for rabbits. There you find only the red blob and an employee. The Blob can buy it for 5,000 Gralats.