Immortals generally eat the same as people. You can worship the three beasts and eat blood.
Buddha and bodhisattva had better be fruit. A glass of water is enough, because buddhas and bodhisattvas let us cultivate a clean heart, and water is the cleanest among all kinds of food.
In fact, whether it is a fairy or a Buddha or a bodhisattva, as long as it is respectful and practiced according to law, it is better than offering anything.