Shirokane Rinko from BanG Dream.
It is 100 official pictures and autotags.
Example prompt for casual Rinko:

shirokanerinko, 1girl, solo, black hair, long hair, looking at viewer, purple eyes, skirt, frills, long sleeves, ribbon, black skirt, shirt, bangs, high-waist skirt, frilled sleeves, blush, white shirt, neck ribbon, hairband, breasts, bow, black ribbon, standing, cslsk

School uniform Rinko:

shirokanerinko, 1girl, solo, buttons, double-breasted, black hair, ribbon, purple eyes, school uniform, long hair, hanasakigawa school uniform, smile, brown dress, red ribbon, bangs, neck ribbon, dress, looking at viewer, pleated dress, sailor dress, long sleeves