Mine don't even like all types of timothy hay.
Sample bags seem like a good idea so you can find out more about what they like without spending lots. Mine have tried 5 of the 6 samples from the Hay Experts, I've ordered one from Hayforpets, and will get one from West Wales Willows at some point.
Have started keeping a list of what they do and don't like, as there's so much to keep track of.
LOVE: Oxbow Western Timothy, Oxbow Orchard Grass
LIKE: Alfalfa King Oat Wheat & Barley, Pets at Home bedding Hay, Excel Herbage [timothy hay with dandelions and marigolds], Comfey Pet bedding hay,
OK: Excel Fresh Forage, Alpine Meadow Hay, Woodlands Herby Harvest (favourite before they discovered Oxbow, now they leave some of it)
DISLIKE: Readigrass, Pets at Home Timothy Hay