ABBA were legends. Their singles and most of their albums are pure genius.
However, they're highly unlikely to release any more "rare" recordings, and certainly not in a high profile EP release.
Bjorn's most recently published interview states quite catagorically that there'll be no more unreleased songs. As far as he is concerned, they did all that with the 45 minutes of unreleased material that they brought out (mostly in medley form) in 1993 and 1994.
It's not true also that Benny wrote all the tunes. Bjorn AND Benny wrote the ABBA songs together, and in the early years they both often wrote the lyrics together too, with assistance with song titles from their manager Stig Anderson sometimes as well.
Since the 1990s however, all new Bjorn and Benny projects (and there have been many) feature tunes written by Benny and lyrics by Bjorn. But this wasn't the case during the ABBA or CHESS years. They both wrote the tunes. They were more "collaborative" than Lennon/McCartney in that respect, and for a much longer period.
ABBA was bourne quite by accident. Both Bjorn and Benny had been successful artists in their own right for a decade prior to forming ABBA and had been writing and producing for themselves and other artists before asking their girlfriends to "help out" with some backing vocals.
Now, after ABBA, they continue to work together on new projects and songs every year and seem very happy. Their greatest achievement as collaborators since ABBA is yet to attain worldwide attention - their epic musical Kristina. It has been massive in Sweden, though and has started to get noticed internationally at last.
Bjorn and Benny's writing talent reaches far greater realms than any other surviving pop composers that I can think of.
While in ABBA, they confined their talents a little. Since let loose from the constraints of writing for their ex-wives they've offered so many different styles. And it's a sobering thought that Benny's current folk band have been together longer than ABBA were together - and they're hugely popular in Scandinavia.
Now that Benny can work with this at his own pace, both him and Bjorn find time to work on other musical projects - something there was no time for them to do while the ABBA machine was thundering along at hyper-speed.
But their musical legacy of eight studio ABBA albums crammed with dozens of musical masterpieces, and their incredible recording techniques - not to mention the amazing vocals of Agnetha and Frida, will mean that ABBAs music crosses over so many generations. And that's why it is still so relevant in today's world.
A good song is a good song.