Difficult, but not impossible, jigsaws that would take time to do.
A solar charger for a power bank to be able to charge some electronics/phones for limited use.
I second the playing cards - and maybe a book of card games/tricks.
Do you have sources of light for entertainment after dark? As candles and torches are not great for reading or detail work, but might be fine for board games. But a lantern (with spare batteries), a tilly lamp with kerosene, or a camping gaz (TM - other brands are available) gas lamp would all be useful for brighter and more constant light in 1 room.
Do you enjoy music? Is it worth having an instrument and an instruction book, to try to learn (or rekindle past knowledge)?
A game we enjoy is QBitz, as it can be for 1 person to play alone, or up to 4 (or more if you get extra sets of the blocks) to play together.
A bag of dice can be useful, in case some go missing from games but also to make games yourselves.
Or some dominoes to make intricate patterns or marble run or lego etc - things that you can design and build, then pull apart and build again differently. Or build and then play with.