Abraham/Jacob.

2:132

The same did Abraham enjoin upon his sons, and also Jacob, (saying): O my sons! Lo! Allah hath chosen for you the (true) religion; therefore die not save as men who have surrendered (unto Him).

Moses.

7:143

And Moses fell down senseless. And when he woke he said: Glory unto Thee! I turn unto Thee repentant, and I am the first of (true) believers.

Muhammad.

39:12

And I [Muhammad] am commanded to be the first of those who are muslims (surrender unto Him).