Various cheeses, always a cured meat on hand (prosciutto or salami or smoked salmon or trout, etc.), cornichons, nuts, lots of chopped up veggies, hummus and sweet potato dip. And my husband's favorite...sardines in mustard on Saltines. And for the kids - house popped corn with chocolate chips.

- plain greek yogurt for savory or sweet yogurt bowls. For a quick little meal the other day i made a few dates via the food 52 sautéed dates recipe, flopped over the yogurt with sliced cucumber on the side to help scoop
- frozen cooked edamame in the pod
- snackable veggies; radishes, baby carrots, cherry tomatoes, cucumbers...
- various nuts and seeds , most often used to top salads or yogurts
- popcorn with nutritional yeast
- frozen chopped mango, i eat it semi defrosted and it's like sorbet
- avocado toast; it's popular for a reason
- vegetarian stuffed grape leaves
- various pickled/brined veggies and such like marinated mushrooms, roasted peppers, gigante beans
- various nut butters; make a quick sesame peanut noodle dish or sauce for seared tofu or ho-hum veggies

Every time i cook i make too much of at least one component- ie i'll roast enough veggies for the dish that night but also to make leftovers, if i'm making a baked potato i bake at least two, etc... so the next day (or day after) i have one component ready to turn into another totally different meal quickly

Thanks to all - great answers!

Tortillas, cheese, sour cream and salsa. Quesadillas are always easy to make

I chop up extra lettuce or kale whenever I make a salad, and store in a ziploc bag. A day later I will make a quick salad with the extra green mixed with whatever leftovers I can scrounge.

fresh fruit, canned tuna, sardines, eggs, canned tomatoes, pasta
Cheese isn't a "quickie" at our house because imho it has to be properly room temperature to be enjoyed, and that takes at least an hour out of the fridge.

Look at your usual meals and see what foods or nutrients are low in quantity or missing (e.g. carbs, potassium, red-colored produce).
Then build those elements into snacks to round out your day or week.

Homemade hummus with veggies
Olives
Chips and salsa
Oven baked spicy chickpeas
Frozen edamame
We also keep frozen gyoza around- they're a great quick meal in a pinch :)

Honestly, this is what I have to snack on: deli container of Italian olives, a jar of marinated vegetables, pickles dill and sweet, hummus, Baby Bel cheese, sliced salami, brick of cheddar amd swiss. Pantry Triscuits, Wheat Thins, water crackers, mixed nuts, Kettle chips, Scoops, salsa. Chicken wings in the freezer. And, of course, carrots and celery in the crisper. And always peanut butter and jelly...white gummy bread 🍞 In the freezer. BB

i have just delved into lavosh wraps. they are terrific. you can vegetarian with hummus and veggies, or carne eater with goat cheese, lamb and sliced red bell peppers. cream cheese, ham and swiss. lettuce and veggies and chicken shreds. salami and provolone. also, for quick meals I've been putting canned refried beans and slices of cheddar on whole wheat tortillas and microwaving with damp paper towel over (seal/fold up well so they don't leak). i always have granola, greek yogurt and fruit for my last choice yummy and quick snack/meal. or lots of salad greens and veggies and a good vinaigrette with sliced cheese.

That's what Trader Joe's is for :-)

Chopped veggies
Fresh fruit (cut up, ready to grab and go)
Homemade or store-bought hummus, nut butters, & yogurt-based dips
Baked cubes of tofu that can be quickly re-heated
Homemade veggie chips
Slices of cheese (I slice extra whenever its out for a salad/meal and save them for a quick snack)
Lettuce/cabbage leaves separated and stored for quick wraps
Jars of nuts and seeds
Homemade granola clusters
Homemade Trail mix
Jars of Dried Fruit
Cold-brewed tea and coffee
Roasted Chickpeas & edamame
Big batches of simply-seasoned salads with veggies or beans (like these! https://food52.com/blog/19218-these-salads-dress-themselves-just-like-you)

Hope it helps!

Apples and bananas with almond butter.
Olives
Yogurt, coconut flakes, seeds and nuts
Carrot sticks and homemade ranch dressing