This extensive catalogue of music by long-forgotten composers is mentioned by Martin Anderson in his latest mailing:
https://www.areditions.com/composer/?goal=0_1d4d20a99c-c5c3171dd0-329615321&mc_cid=c5c3171dd0&mc_eid=2ffe1271b8 (https://www.areditions.com/composer/?goal=0_1d4d20a99c-c5c3171dd0-329615321&mc_cid=c5c3171dd0&mc_eid=2ffe1271b8)