Someone posted on 2ch their list of favourite eroge songs, and lyceecard.blog.fc2.com picked it up here. I’ll just list them down with names and singers. You might be able to discover some good stuff here.
Title: Ashita no Kimi to Au Tame Ni [VNDB.org]
Song: 明日の君と逢うために OPムービー
Singer: 橋本みゆき
Title: Amesarasa ~Ame to, Fushigi na Kimi ni, Koi wo suru~ [VNDB.org]
Song: アメサラサ～雨と、不思議な君に、恋をする～ OP
Singer: Duca
Title: Little Busters! [VNDB.org]
Song: リトルバスターズ！ 挿入歌「Alicemagic」／Rita
Singer: Rita
Title: Kara no Shoujo [VNDB.org]
Song: 殻ノ少女 OP
Singer: Shimotsuki Haruka
Title: Trample on Schatten!! [VNDB.org]
Song: Trample on Schatten!!～かげふみのうた～ OP
Singer: 青葉りんご
Title: G-senjou no Maou [VNDB.org]
Song: G線上の魔王 挿入歌 Close Your Eyes
Singer: 彩音
Title: Love-Bride Eve [VNDB.org]
Song: ラブライド・イヴ OPムービー
Singer: 詩月カオリ
Title: Hello, Goodbye [VNDB.org]
Song: Hello,good-bye OP
Singer: 奥井雅美
Title: Sekai de Ichiban Dame na Koi [VNDB.org]
Song: 世界でいちばんNG（だめ）な恋 OPムービー
Singer: 片霧烈火
Title: Boku ga Sadame Kimi ni wa Tsubasa wo [VNDB.org]
Song: 僕がサダメ君には翼を OP
Singer: カヒーナ
There’s a lot more. Click on this link to see the rest.
I really would have killed you Aaeru if you didn’t include Rita
I don’t understand why KOTOKO or Sakikabara Yui is not included in here O_O;;
I think they’re good singers, especially Sakikabara Yui, who has several albums and singles herself.