As @petaluman said, check out much of the ECM catalog, past and current.
While most of it will be more 'progressive' than the Magnus Ringblom Quartet, it will also be somewhat introspective in tone and mood, like the Magnus Ringblom Quartet.
In other words, despite a lot of the artists on the ECM label being as quiet sounding, it will still have more fire in the soling, complexity, and get a bit more ’outside’ (without being avant-garde).
Here’s a short list of what this great label has to offer:
Eberhard Weber - Colours of Chloe. Later That Evening, Yellow Fields
Pat Metheny - Bright Size, Watercolors, As Falls Wichita, So Falls Wichita Falls
Craig Taborn - Daylight Ghosts
Jan Garbarek - Jan Garbarek / Bobo Stenson Quartet, Of Mist and Melting
Tord Gustavsen - Extended Circle, The Well
Azimuth - Depart,
Ralph Towner - almost anything with Towner on it is worth checking out. As well as his own recordings, he guests on a lot of other recordings.
Ketil Bjørnstad, David Darling, Terje Rypdal, Jon Christensen - The Sea,
Sidsel Endresen - Exile
Anat Fort - A Long Story, And If