I love my balcony

It overlooks a medium-busy street in a neighborhood of Seattle, so I can still people watch. I love the oaks right in front of the building that make my view green and lush, (they do have cankerworm problems, but nothing's perfect) and even in the winter, give enough of a natural feel that the place doesn't feel sterile. It's a nice mix of urbanity and green space.

I'm on the second floor, and the balcony is this fun not-quite outside and not-quite inside in between space. Like, It's ambient temperature and noise, so I need to wear warm clothing in the winter, but I can leave things outside and not worry about them getting messed with. (within reason)

I've got a Sarracenia pitcher plant on the table. It deals perfectly well with this temperature zone, so it'll go dormant in winter and come back in the spring. There's (mostly unproductive) strawberry in one of the floor planters that gives me a few of the tastiest berries every year, and a bunch of shiso plants next to it, which are great for sushi. In the little hanging pot, there's a hens and chicks plant, and some native ferns (sword and deer ferns) in the planter on the railing. I have another planter sitting unused, and I want to hang it on the railing above the strawberries.

Any suggestions as to what I should put in there? More ferns?