An Evangelist is one who goes out to proclaim the Gospel of Jesus Christ.
General references to Evangelists:
11 And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; (Eph 4:11 KJV)
Specific examples of Evangelists:
Philip
5 Then Philip went down to the city of Samaria, and preached Christ unto them.
6 And the people with one accord gave heed unto those things which Philip spake, hearing and seeing the miracles which he did.
7 For unclean spirits, crying with loud voice, came out of many that were possessed with them: and many taken with palsies, and that were lame, were healed.
8 And there was great joy in that city. (Act 8:5-8 KJV)
26 And the angel of the Lord spake unto Philip, saying, Arise, and go toward the south unto the way that goeth down from Jerusalem unto Gaza, which is desert.
27 And he arose and went: and, behold, a man of Ethiopia, an eunuch of great authority under Candace queen of the Ethiopians, who had the charge of all her treasure, and had come to Jerusalem for to worship,
28 Was returning, and sitting in his chariot read Esaias the prophet.
29 Then the Spirit said unto Philip, Go near, and join thyself to this chariot.
30 And Philip ran thither to him, and heard him read the prophet Esaias, and said, Understandest thou what thou readest?
31 And he said, How can I, except some man should guide me? And he desired Philip that he would come up and sit with him.
32 The place of the scripture which he read was this, He was led as a sheep to the slaughter; and like a lamb dumb before his shearer, so opened he not his mouth:
33 In his humiliation his judgment was taken away: and who shall declare his generation? for his life is taken from the earth.
34 And the eunuch answered Philip, and said, I pray thee, of whom speaketh the prophet this? of himself, or of some other man?
35 Then Philip opened his mouth, and began at the same scripture, and preached unto him Jesus.
36 And as they went on their way, they came unto a certain water: and the eunuch said, See, here is water; what doth hinder me to be baptized?
37 And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God.
38 And he commanded the chariot to stand still: and they went down both into the water, both Philip and the eunuch; and he baptized him.
39 And when they were come up out of the water, the Spirit of the Lord caught away Philip, that the eunuch saw him no more: and he went on his way rejoicing.
40 But Philip was found at Azotus: and passing through he preached in all the cities, till he came to Caesarea. (Act 8:26-40 KJV)
Paul
16 But rise, and stand upon thy feet: for I have appeared unto thee for this purpose, to make thee a minister and a witness both of these things which thou hast seen, and of those things in the which I will appear unto thee;
17 Delivering thee from the people, and from the Gentiles, unto whom now I send thee,
18 To open their eyes, and to turn them from darkness to light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith that is in me. (Act 26:16-18 KJV)