Teen sensation George North tops the list that includes fellow current internationals Morgan Stoddart, Rhys Priestland, Tavis Knoyle, Josh Turnbull and Rob McCusker.
The news will be a major boost to the west Wales region particularly as a number of English clubs were looking to snatch the likes of North and Stoddart from the Scarlets.
Davies reckons the re-signed players will form the backbone of the Scarlets in future years as they strive for Magners League glory.
"There's a core group of players here, most of whom have developed over the last couple of years, who still have a lot of development in them and who will become the bedrock of this Scarlets team moving forward," said head coach Davies.
"This announcement underpins this ethos we have had of developing from within.
"To name 21 players of this quality who are virtually all Welsh and who have come through our system or who have developed through our system is great for the region.
"We were under a lot of pressure externally because a lot of these players had made names for themselves.
"Re-signing some of them has not been cheap, but we had to prioritise something and for me it was ensuring this group of players remain Scarlets for the next couple of seasons at least because they have got that much development in them again.
"These players can only get better and as a result the team will get better and by securing their future we can be confident moving forward.
"If you look at some of these names and how quickly they have come through in the last few years, if they can maintain that progress, who knows?"
The Scarlets will need all of their youthful exuberance if they are to triumph in the crunch Magners League encounter with Ulster on Friday night.
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