Snowshoeing in the winter

An inflatable stand-up paddleboard in the summer

Birdwatching all year round

Each of those is a bit of a pricey investment initially (around $300 for a good new set of binoculars / an inflatable SUP / a snowshoe bundle) but gets you more than a few years of use out of them, and gives you quite a few things to do all year round.

And, as mentioned, look on FB Marketplace for used/cheap gear, such as a mountain bike or kayak.