What Christian denominations profess that they remain with 'that which was from the beginning' rather than 'progress' to a 'further revelation'?

That is a very important point – that the Reformation was not new revelation, but a return to what Christianity had been when the apostle John had emphasised the need to hold to that from the beginning, “That which we have seen and heard” (i.e. Jesus Christ). Christianity needs to hold fast to biblical truth, declaring and living it, while waiting for Christ to come from heaven.

This was shown in John Calvin’s 1539 response to Cardinal Sadoleto’s attempt to persuade the city of Geneva to return to the Roman fold. Calvin explained why that would be a retrograde step by dealing with four topics that are just as relevant today as they were in the 1500s: to recover a truly biblical understanding of worship, to reassert the doctrine of justification by faith alone, to regain from Scripture an understanding of the central importance of baptism and the Lord’s Supper, and to seek to conform the mode of church government more closely to the biblical model.

There are very many denominations today that publicly confess that stance. I only have time to give a couple of examples. The first one is printed in every edition of ‘Sword’ magazine. It states one purpose for the magazine. That it

“is published to bring the unchanging word of God to the people of God and through them to the nations of the world. .. The One who was the horizon of ancient Israel’s prophets is the central message of the apostolic Church in every age. The Jesus-centred Church is God’s prophet to the world – a letter from Messiah. Jesus intends His Church to proclaim His word and reveal His Living Presence to the world, empowered by the Holy Spirit… God’s nature is unchanging. He still communicates through the Holy Spirit as in biblical times. As the full and final revelation of God, Scripture can neither be added to nor taken away from. Without the Holy Spirit we are left with only our rational minds to interpret the written word. With the Holy Spirit’s help. The written Word of yesterday becomes the living Word of today, revealing everything necessary for godly life and salvation…”

A problem with regard to your question, though, is that this magazine is not a denominational one. The people producing it and writing for it come from a range of Protestant denominations. The readership comes from an even wider range of Protestant denominations.

However, the denomination of the Free Church of Scotland has this on its public web-site:

“Perhaps the most obvious feature of the Free Church is the centrality of the Bible in all that we do. The Free Church believes that the Bible is the inspired Word of God. Consequently, everything from our patterns of worship to our church structures seeks to reflect clear Biblical teaching. That’s why, for example, in our worship we sing only the truths of the Bible, hear them read, explained, and applied to our lives in a sermon, and pray for God’s promises in the Bible to be fulfilled in our various circumstances.

The central focus of the whole Bible is to be found in a person – Jesus Christ. Because the Free Church is a Bible Church it is also a Jesus-centred Church, a Gospel Church. Of course, the Free Church is historic. It traces its roots to 1843 and the struggle of the Scottish church to remain ‘free’ from State interference, beyond that to the Protestant Reformation of the 16th century, and beyond that again to the Early Church. However, at the heart of the identity of the Free Church of Scotland is a passion for sharing and living the good news about Jesus Christ – the gospel. So, in all our congregations each Sunday you will hear the same wonderful message explained from the Bible and applied to everyday life: Jesus Christ, both fully God and fully human, came into the world to seek out and rescue lost, sinful men and women, by bearing their guilt and condemnation on his Cross and rising again to life in victory over sin and death and hell. Because of him Christians live transformed lives. It is this message, far more than any historic or cultural distinctive, that defines us. This is what we are about.

The gospel message is for everyone. Jesus commanded his church to ‘go and make disciples of all nations’ (Matthew 28:19). The Free Church of Scotland takes that command seriously and seeks to bring the gospel to every person in Scotland, and in partnership with other churches, to the whole world.”

So, there are a couple of 21st century examples of what you seek. I hope others will supply more examples.