A lot of names have already been mentioned in other answers. So, I will try to add a few more names which have been missed.
Gracy Singh : The graceful and beautiful actress from Lagaan, seems you have disappeared. She acted in few more movies but she is not seen making any presence on-screen since quite a few years.
Anita Raj : She did good nunber of movies and was popular too but she disappeared after those movies. She made a comeback on small screen.
Amrita Arora : Not that she had amazing acting skills or anything but she tried for few years but now she has almost disappeared.
Koena Mitra : TThere was a phase when her presence could be felt very much on-screen. But, gradually she disappeared. She had acted in movies like Apna Sapna Money Money.
Payal Rohtagi : She had made numerous controversial statements and I believe she still does that. However, she seems to have disappeared from the big screen.
Yukta Mukhee : The beautiful actress had started in few movies but she could not make it big.
Diana Hayden : Another beautiful lady who had no luck in Bollywood and disappeared from Bollywood.
Trisha Krishnan : She is a popular name in the south movie industry bit disappeared from Bollywood after doing Khatta Meetha.
Kajal Agarwal : Another popular name from south movie industry who appeared in the Hindi movie Singham and then disappeared.
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