What's "they/any"?
Glad you asked!
Put simply, "they/any" behind someone's name (like Calista's) means that they use multiple sets of pronouns, but they/them is usually a good default. The specifics vary from person to person, but for Calista, it means just that: they don't mind whether you call them "him", "her", or "them," and in fact they love hearing a mix of all of them. That's why you'll see her referred to multiple ways on this website!
But why?
Every single person who uses multiple sets of pronouns has a slightly different definition of what it means for them and why they use multiple rather than one or another. This individual, customizable approach is very common in the LGBTQ+ community, across identities: if you put two people who use the same term in a room together, chances are they'll each use that term for different reasons and have slightly different ideas of what it means. This is okay! It's all part of creation and discovery with the one art medium you've got access to for your whole life: yourself!
Calista likes to think of their pronouns--and their genderqueer identity--as a work of art they're constantly creating. Take Van Gogh's Starry Night, for instance: when you first see it, you could easily say it's blue. But take a closer look, and you'll see there are also big streaks of yellow and white right across the middle, and a tree of black and brown rising up one side. And each of those colors has many different shades and tints represented in the painting, and there are other colors besides! Without even just one of those colors, the painting wouldn't be quite the same, and they all come together to form a beautiful image.
In just the same way, when you first see Calista, you could easily say she's a woman. And you wouldn't be wrong! But take a closer look, and there are many aspects to her femininity, and to her masculinity, and to qualities that all genders share, and to who she is outside of her gender. All of these hues and shades and tints combine to make Calista.
That's why they feel just one set of pronouns doesn't fully cover who they are. They are blue and pink and yellow and purple, not or.