Mainly via online discovery as by the time I got into jazz, Mosaic was well past it's groundbreaking heyday. But that was for other Mosaics such as the Selects they were carrying (RivBea Orchestra) and the remaining singles like the George Wein in Mexico, Bud Freeman Chicago High School, & The Jazz Piano which made up my first orders from them about 6 years ago. The first box sets I ordered from the were some of the last vinyl sets they had like the Kirk, Coltrane and Mulligan sets.
I got into Tina Brooks much later and mainly through the Audio Wave XRCDs; learning later about Mosaic's efforts to get the Brooks albums back in print domestically. That probably paved the way for the recent Brooks reissues, and well deserved IMO. The trio of albums from him that include Back to the Tracks, True Blue & The Waiting Game are remarkable. I actually don't have any version of Minor Move, and will remedy that eventually even though it's regarded as his least essential output.