He was the first cricketer to wear a helmet in a full Test match
Lala Amarnath was the first Indian to score a Test Match Century
The first cricketer to wear a protective helmet was Graham Yallop of Australia. He first demonstrated this piece of revolutionary equipment on the 17th March 1978, in the second test match of the series. Yallop was actually one of the few Australian batsmen to do well, making 47 in the first innings. There's a picture of him in the related links section on Cricinfo.
Charles Bennerman of Australia scored the first century in the first inning of the first Test Match in 1877.
I know Sourav Ganguly is the one of them
Lala Amarmnath was the first cricketer to score a Test century for the Indian cricket team.