Huh. I've owned the Sam Rivers Mosaic for years, but never thought of it as a "Free Jazz" box...maybe disc 3, but otherwise pretty straight-ahead. Perhaps Free Jazz can be thought of as a continuum with "abstract" at one end and "noise" at the other, but not sure it encompasses "melodicism." Anyway, for Free Jazz box sets, Coltrane's Live in Japan, also Impulse Box Sets 4 and 5. Sun Ra's Artyard In A Box. And how about: