Acitvity supplies to keep on hand for toddler ?

Hello! My son is 17 months and soon we’ll be into the super cold rainy season where we live which means limited outdoor time. I want to start building up like an activity supply closet so I can keep stuff on hand to do activities with and to keep him busy.

I’ve tried Pinterest but most of the things are just one time uses. Im looking for stuff I can pull out and either make an activity or do something. If I’m making any sense I’d love to hear your suggestions!!