Things I like to learn about in no particular order...
Shells (I have another box too)
Butterflies (& tangentially butterfly gardens)
Gardening (and making zucchini bread when the harvest is good. And taking pictures of my harvest shaped like smiley faces. Also, have you eaten zucchini flowers before?)
Astronomy
Bugs
Cows (And statues of cows)
Lichens *totally different from mushrooms, but equally weird
Birds (also birds on things. It just always cracks me up when a pigeon lands on a statue's head)
Trees & Identifying trees. Also trees that have grown around things/eaten things/overcome things. Nature amazes.
Chances are there will be poems, articles, or picture books with these topics at some point in my career.