Have a look around a chinese or asian kitchenware store or grocer. There are those little condiment dishes that you probably see at yum cha with relatively high walls for its size. Those can work but they're not my favourite.
Usually at those same stores, you'll find condiment dishes that are flatter and wider like this one:
https://www.amazon.com/Dipping-Dishes-Porcelain-Watercolor-Palette/dp/B07RQVKCDM
Those are my preferred once as the extra surface area can quickly cool down whatever your taste testing.