The kit is from Kotobukiya's Frame Arms Girl product line; Specifically, Frame Arms Girl Materia.
She's also wearing a dress from the Picco Neemo line. Picco Neemo is Azone's line of 1/12 scale dolls and clothing. Frame Arms Girl Materia can wear most Picco Neemo clothing without problems.
Another thing you can do is to combine Frame Arms Girl with Custom Lily. Custom Lily is a variation of the Assault Lily line of dolls. While Assault Lily's characters have names and backgrounds, Custom Lily characters don't. Custom Lily characters are meant to get customized by the customer.
While the original packaging looks like this:
I combined mine with Frame Arms Girl Materia, created an additional head joint, and ended up with two "dolls" which are pretty much family.
The dresses they're wearing are from the Picco Neemo line.
Not everything was perfect out of the box for this setup. I had to create a neck joint to attach the Custom Lily doll head parts to Frame Arms Girl Materia's body.
I also needed some way to create an internal headpiece (the white part in the photo below). Without this part, the doll's face piece and hair will be unsupported. Custom Lily only includes one of these pieces.
...so I created a duplicate using epoxy putty. I covered the original doll head pieces in baby powder when making duplicate pieces so the putty wouldn't stick to them.
You can also combine Picco Neemo or Frame Arms Girl Materia bodies with figma or S.H.Figuarts action figures' heads. The head sizes might be out of proportion and you might need to create customized neck joint pieces but doing so will open up all kinds of possibilities.
figma Kirino Kousaka head + Custom Lily 2.0 (Picco Neemo S White 2.0) body + Picco Neemo dress
figma Kirino Kousaka head + Picco Neemo S White 1.0 body + Picco Neemo dress
Left: Frame Arms Girl Materia White body + Custom Lily 2.0 Type-B Black head + Picco Neemo dress
Right: figma Mio Akiyama head, bass + Frame Arms Girl Materia body + Picco Neemo dress
S.H.Figuarts Chibi Moon head + Frame Arms Girl Materia body + Picco Neemo dress
Where to buy Custom Lily: Amiami | Hobbylink Japan | Hobby Search
Where to buy Picco Neemo: Amiami | Hobbylink Japan | Hobby Search
Where to buy Frame Arms Girl Materia: Amiami | Hobbylink Japan | Hobby Search