Good question, talking slim girls here.
Implants on their own would be Lan/Enosa, I’d guess 600cc to 750cc but I can’t be sure as she wouldn’t tell me exactly. Naomi/Layla/Rose in her earlier days for having the biggest boobs with implants, and the biggest naturals on a slim girl would be Chinese Fiona from GC pre covid. I’d also give a special mention to the famous Didi, who while she had DDs , I’d always wondered how big her boobs really were before she had them reduced.