The bento stash

To make your bento efforts less time consuming, I would recommend to work with a bento stash. I think most people are familiar with the term freezer stash, where you save your leftover meals for later. This works great for bento too. I think that the bento stash can be separated into two different types. Type 1 is food that you can store in your freezer (or where needed), take it out, place it in your bento and be done with it. The 2nd type are the things that are handy to have in storage but do require some prep work before you can put it in your bento. I will provide a list with things that I think are handy to include in your bento stash, for inspiration. Do keep in mind that you don’t have to have ALL these supplies at once. Just keep a few at hand and when you find a nice discount you can buy in bulk and store it in smaller portions for later use.
Some handy things to have when building up a freezer bento stash are clingy wrap or very small containers which can hold bento sized portions. 

Main dishes:
I almost always use a main dish that I prepared the night before for dinner, or that comes from my freezer stash. Some things that work great at room temperature are fried rice dishes, pasta dishes, noodle dishes or curries. Also stuffed wraps and chili can be used in a bento. All kind of pancakes, muffins and vegetable pies are another thing that makes a great main dish. Most of these main dishes fall into the type 1 stash. You can just get it out of the freezer, defrost (sometimes this isn’t needed) and put it in your bento. Another thing that is easy to include is onigiri. I just make those in bulk, store them in clingy wrap in the freezer and include them in a bento just like that. Soup is also a great main dish, but you will need a thermos bento to keep it warm and prevent leaking. If you have access to a microwave, then your possibilities are ever greater. A favorite here for a dinner bento is lasagne. 

Side dishes:
The possibilities with your side dishes are almost endless. I will just toss some ideas, but I am sure there is a lot more to choose from. Some dishes and ingredients you can just buy and use, others you need to prepare first and add them to your stash. 

Type 1 foods:
(Vegetarian) meatballs
Mini onigiri
All kinds of nuts
Peas & (baby) corn
Edamame (soy beans)
(Vegetarian) sausages
Paprika (slice & freeze them)
All kinds of cheeses
Frozen berries
Mini hamburgers & (vegetable) patties
Mini muffins & mini pancakes
Falafel Risotto balls

Type 2 foods:
Broccoli & cauliflower (both can be frozen)
Dumplings (and other likewise foods)
Potatoes & sweet potatoes
Snow peas
Eggplant & courgette (both can be frozen)
All kind of beans

Great foods that you can keep for at least a week (make sure you check the quality before buying!):
Apples & pears
All kinds of tomatoes

Of course it is still nice to add something freshly made to a bento when you have the time for it. Especially various kinds of salads are best when made on the same day. But even those you can make in bulk and keep in the fridge for a few days. I hope this information is useful to you and remember that this is only a glimpse of what is possible to include. Don’t make bento more difficult than it needs to be and you can get a lot of satisfaction out of it.