There were only 12 Apostles of the Lamb. Together, they were a irrefutable witness of the baptism, ministry, death, and ascension of Jesus Christ.
“Therefore, of these men who have accompanied us all the time that the Lord Jesus went in and out among us, 22 beginning from the baptism of John to that day when He was taken up from us, one of these must become a witness with us of His resurrection.”
“You, O Lord, who know the hearts of all, show which of these two You have chosen 25 to take part in this ministry and apostleship..."
It should be noted: another apostle listed in scripture did not meet these requirements. Therefore, he could not be numbered among the 12. No matter his contribution to the scriptural testimony (God does not esteem men like men esteem themselves) he could not have given eye-witness testimony of the ministry, death, resurrection, and ascension of Jesus.
Of course I'm talking about Barnabas.
"But when the apostles Barnabas and Paul heard this, they tore their clothes and ran in among the multitude, crying out..."
Paul was another apostle who was not among the 12 Apostles of the Lamb. Paul even wrote as much:
In Acts 6 this is recorded: "Then the twelve summoned the multitude of the disciples and said, “It is not desirable that we should leave the word of God and serve tables."
The twelve now included Matthias.
Then Paul wrote this: "For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, 4 and that He was buried, and that He rose again the third day according to the Scriptures, 5 and that He was seen by Cephas, then by the twelve..."
Paul did not number himself among the twelve. He, like Barnabas, Timothy, Silvanus, were other apostles mentioned in the Bible, not Apostles of the Lamb as seen in Revelation:
"Now the wall of the city had twelve foundations, and on them were the names of the twelve apostles of the Lamb."
Of course the apostolic gift is foundational as is the prophetic gift. God intended that those gifts work together. Why? Because it is given to the prophets to hear God directly (vital to the life of a believer) and to teach others to hear God. And it is given to the apostles to know and establish the administration and organization of the church and to correct any weakness thereof. God did not remove the need for people skilled with these gifts. Indeed, as the world rushes to the end, knowing what God is doing and how He is doing it will become more and more important to those who are spiritual.
Last note: although demonstrations of power may be necessary, the life of an apostle will primarily be identified as one who builds up the Body of Christ, loves and supports the saints, and devotion to the Lord in all things. Humility and reverence for the Lord will follow him. Many would testify of his kindness and grace.
However, like the Lord, apostles may often create conflict: primarily strife between the spiritually minded and the worldly. A faithful apostle will be lied about, ridiculed, and slandered. Assured of his place in Christ, he will likely remain silent as others disparage him.