In chronological order of their major solo debut years, they are:
1980 - 松田 聖子 (Matsuda Seiko; 2 more, and here's my favourite song!
) 1985 - 南野 陽子 (Minamino Youko; and this is my favourite song!
) 1987 - 酒井 法子 (Sakai Noriko)
1987 - 森高 千里 (Moritaka Chisato; and nearly all her singles on this list from 18yo until 30yo in 1999, when she retired and married!
)1991 - 坂井 泉水 (Sakai Izumi also known as ZARD; and nearly all her singles on this list until she died in 2007 at only 40yo...
)1995 - 安室 奈美恵 (Amuro Namie)
1998 - 浜崎 あゆみ (Hamasaki Ayumi; and nearly all her songs until mid or late 2006, when I started losing interest in her new songs...)
1998 - 宇多田 ヒカル (Utada Hikaru; and ALL the remaining songs in this album!
)2001 - 松浦 亜弥 (Matsuura Aya; and I can't resist including one more song!
)2002 - 藤本 美貴 (Fujimoto Miki)
2003 - 玉置 成実 (Tamaki Nami; and once again, I can't resist including one more song!
)2003 - 大塚 愛 (Otsuka Ai)
Clicking on all those 80 different links,
, should lead to some of my favourite songs by each singer, as well as some H!O threads or wiki articles, I hope... 
Finally, I'm done! This post took me quite a few hours to prepare... nearly half a day, I think!
