This is a difficult question to answer if you don't use alignment in your games. I have disliked the alignment system since the mid-eighties and ditched it altogether in 1990. I haven't used it in any edition of D&D since. And, of course, it doesn't exist in most other role-playing games.
In my various GURPS campaigns (my usual go-to system), PCs have a mix of personality traits. Some of them are more selfish than others. Some are more altruistic. Maybe some of them would land on the bottom half of ye olde alignment grid? I'm not sure. Usually, they evolve in unexpected directions over time. Most PCs generally become better people over the course of our campaigns. Though I have GMed for a few who succumbed to their baser instincts. I think all of them either died or retired from the adventuring group (usually becoming NPCs).
In my various GURPS campaigns (my usual go-to system), PCs have a mix of personality traits. Some of them are more selfish than others. Some are more altruistic. Maybe some of them would land on the bottom half of ye olde alignment grid? I'm not sure. Usually, they evolve in unexpected directions over time. Most PCs generally become better people over the course of our campaigns. Though I have GMed for a few who succumbed to their baser instincts. I think all of them either died or retired from the adventuring group (usually becoming NPCs).