Mine would be
A Stuart (AUS)- he took a hat-trick against Pak and after that never heard his name again.
Gary Stead ( NZ ) - Scored a good fighting half century against India when NZ last toured India but never heard of him again after that series.
David Johnson ( Ind ) - Was the highest wicket taker against provinial teams when India toured SAF in 1997 , got to play in one test , took 2-47 and was dropped from even his state side Karnataka within 6 months.
Vikram Rathore ( India ) - Scored tons and tons of runs when he was with the Indian team in 1996-97 against County teams in Eng and Provinces in SAF but failed miserably in Test matches.
I remember Gavascar saying about a player ( can't remeber his name ) who made debut for India in the same series in which he did - that he was a very very talented player and one of the best he has seen . He was brilliantly caught by Sobers when he was playing well in his only innings and after that he never played for India again. While in the same series , Sobers dropped 2 very easy catches in his 1st test innings and after that he never looked back. He was saying how luck plays an important part in one's career.