From personal experience, I know it can be hard coming up with archetypes and things and I came across some generators that (honestly) have been super helpful when i’m stuck in a rut with what I want to write.

• here’s a archetype generator and here’s a personality generator
  
• this one generates different motives and it’s honestly really cool
• here’s a family tree generator like how many siblings they may have
  and if their parents and grandparents are in good health.
• this ones an appearance generator and it’s honestly a+++
• okay okay this one is one that just throws things together to make
  maybe a background character and it includes things like their
  religion and their job