Compass Records carries most (all?) of the albums which were originally released by Green Linnet. They also have albums from other companies such as Mulligan Records, Xenophile, Celtophile, and Tayberry.
Loftus Music was started in 2007 by Kevin Burke, a wonderful Irish fiddler, as a way to produce his own recordings and recordings that he was involved in with other artists.
In particular, here are some artists you can find at those two titles who I would highly recommend:
Kevin Burke. Wonderful Irish fiddler, does traditional Irish fiddle music, also fiddle music from other parts of Europe.
John Cunningham. A great Scottish fiddler, now sadly deceased.
Celtic Fiddle Festival. Originally Kevin Burke, John Cunningham, Christian Lemaître, and Ged Foley, this was my introduction to Celtic fiddle music. Their albums are wonderful. In 2003 John Cunningham unexpected passed away, André Brunet joined the group and the album Play On is the first one released after that. (I’m not going to say that Brunet filled Cunningham’s spot, since those shoes would be almost impossible to fill & Brunet has a somewhat different style of music than Cunningham did; while Celtic Fiddle Festival’s music changed a little bit after the loss of Cunningham and addition of Brunet, both lineups are still wonderful. If you ever have a chance to see them live, don’t pass it up.)
Martin Hayes. Either solo or with Dennis Cahill, another incredible Irish fiddler.