The short answer is whatever characters the story needs, but that's something of a cop-out. Much as we all like to vary our characters, most authors have a tendency to gravitate to some particular kind of character, whether that's a matter of gender, age, personality or lifestyle. So what kind of characters do I like writing about?
One thing I have noticed is that I seem to like writing about teenagers. Not in a YA sort of way, since the perspective tends to be standing a little apart and making gentle fun of the naivety and silliness of adolescence. It's not really a new thing, though. From what I can remember of the stories I was creating at about ten or eleven (none of which have survived) the important characters were always between about sixteen and eighteen — which, of course, was very grown up then, although perhaps young enough to be relatable.
When I started writing The Winter Legend, in my later teens, most of the main characters were still of a similar age, and this has largely survived innumerable rewritings through the decades. And I still use characters of that age a good deal. Estent, the protagonist of The Treason of Memory, is around eighteen, although his age isn't given in the story. Zadith and Musu, in The Lone and Level Sands, are a little older, but not much over twenty, while my recurring characters Kari and Fai (Steal Away, The Temple of Taak-Resh) are around sixteen or seventeen.
Not everyone's that young. The Traveller measures his age in millennia, and the age he "stuck" at is around thirty, but he's in his teens during a number of the chapters in At An Uncertain Hour.
On the other hand, I do like watching characters grow up. The Winter Legend covers about twenty-five years, and the central characters go from teens to early forties, turning from the struggling young heroes to the wise guides, in much the same way that Obi-Wan grows through the Star Wars films.
Perhaps my favourite example of this is Eltava, MC of seven published stories as well as having a cameo in At An Uncertain Hour. In the earliest story I've written about Eltava, Witch, she's fourteen (though I do have flashbacks in a couple of stories to her as a little child), but I've shown her through her twenties, thirties and forties, right through to Storm-Blown where she's in her late sixties. It's been a fascinating ride to watch her growing and developing while still remaining essentially the same person.
In gender terms, although I haven't done a statistical count-up, I suspect I have a roughly 50-50 split, although if anything my first instinct is more often to focus on a female. That's something which has certainly changed through the years. When I was first writing, almost all my POV characters were male, and I deliberately set myself the aim of using more females, but that seems to have become a matter of instinct now.
I'm not sure why this is, but perhaps it has something to do with otherness. Unlike some authors, I don't create characters to explore myself. I prefer to explore what it's like to be someone completely unlike myself and, though I can certainly do that with male characters **, being a female for a story gives the otherness an extra kick.
As for lifestyle, I tend to write about characters who are pretty much footloose wanderers. Perhaps that's an element of wish-fulfilment, since part of me has always been attracted to the idea of being a rootless traveller, although that's balanced by the other part that wonders how I'd lug a thousand-odd books around with me. Perhaps having a very large ship all to myself would help.
The Traveller and Eltava are both wanderers for life, although the Traveller might spend a decade, or even a few centuries, in one place sometimes. Kari and Fai, in their inimitable adolescent style, are homeless, outlaw sorcerers and love every moment of it. Even people with more roots and responsibilities tend to be wanderers, like Ferriji, the protagonist of Present Historic, a middle-aged international diplomat who travels constantly across the world trying to save it from itself.
Other people have wandering thrust upon them, like Estent, who begins The Treason of Memory with a place in his society (quite a high place, too) and finishes it as a homeless exile. In the final part of The Winter Legend (currently finished but by no means finished with) someone from a primitive mountain tribe refers to the difference between those who "stand above the valley and make sure everything [they] can see is as [they] want it" and those who want " to travel to the distance, as I do, and see what’s beyond it." She adds that it's important to have both kinds of people, and I can see her point, but travelling to the distance is more interesting to write about. For me, at least.
So there are a few of the character types I like to write about. I've created all kinds who are utterly different, but, if I switch off and just write by instinct, the chances are I'll be writing about a teenaged wanderer who wants nothing more from life than to discover what's beyond the distance.
** I've never been three thousand years old, I've never sailed the world on an enchanted ship, and I've never led an army. Just thought I'd mention that, in case you were wondering.