This list of nuts and seeds can give you ideas for healthy snacks and healthy packed lunches.
These are culinary nuts--food items regarded as nuts. That's somewhat different than botanical nuts.
In botany, a "nut" is a kind of fruit with a precise definition:
A fruit with a hard shell; a seed within that is unattached to the shell; and the shell never spontaneously opens to release the seed.
The definition is not very relevant to culinary nuts.
A culinary nut is just whatever is thought of as an edible nut. It's generally a kind of edible fruit with a hard shell, or it may be the edible seed of a fruit.
Family: Fagaceae
Chestnut
Chinkapin
Family: Betulaceae
Filbert
Hazelnut
Family: Anacardiaceae
Cashew
Pistachio
Other family members: mango, poison ivy, poison oak, poison sumac.
Family: Leguminosae
Peanut
See Types of Vegetables for other legumes.
Family: Arecaceae
Coconut
See List of Fruits for more palm family fruits.
Family: Pinaceae
Pine nut
Pinyon
Family: Proteaceae
Macadamia
Family: Rosaceae
Genus: Plum
Almond
See List of Fruits for more Rose family fruits.
Family: Lecythidaceae
Brazil nut
Paradise nut
Family: Juglandaceae
Black walnut
Butternut / White walnut
English walnut / Persian walnut
Heartnut / Japanese walnut
Hickory nut
Pecan
Family: Compositae
Safflower
Sunflower
See Types of Vegetables for other members of the Composite family.
Family: Linaceae
Flaxseed
Family: Cucurbitaceae
Pumpkin seed
See Types of Vegetables for other members of the Gourd family.
Family: Pedaliaceae
Sesame seed
Family: Papveraceae
Poppy seed
The Food and Drug Administration has created a list of tree nuts for the purpose of labeling allergic ingredients.
In 2004, the Food Allergen Labeling and Consumer Protection Act (FALCPA) identified "major allergens," believed to be responsible for 90% of true food allergies. It directed that these allergens should be labeled when they are ingredients in food.
The major allergens are: milk, egg, fish, Crustacean shellfish, tree nuts, wheat, peanuts, and soybeans.
Tree nuts are major allergens, and so are two legumes: peanuts (a culinary nut) and soybeans.
Almond
Beech nut
Brazil nut
Butternut
Cashew
Chestnut (Chinese, American, European, Seguin)
Chinquapin
Coconut
Filbert / Hazelnut
Ginko nut
Hickory nut
Lichee nut
Macadadmia nut / Bush nut
Pecan
Pine nut / Pinon nut
Pili nut
Pistachio
Sheanut
Walnut (English, Persian, Black, Japanese, California), Heartnut, Butternut
The FDA's Guidance notes that this list "may include a species that has no food use"!
Source: Food and Drug Administration, Guidance for Industry: Questions and Answers Regarding Food Allergens
Even though most nuts are not closely related, it's not uncommon to be allergic to all nuts.
Few people, however, are allergic to coconut.
I'm going to refer you to the excellent site Food's Healing Power for fascinating, user-friendly information about the health benefits of nuts!