Currently, I do not have a license for ArcMap and I am wondering if it is possible to get data from an ArcSDE without ArcPy. I have been able to leverage GDAL to read / write to a file geodatabase but am curious if anyone has accomplished this before.
You can connect to a geodatabase via SQL to query any tables within that database.
If the tables are also registered within a geodatabase as Object or Feature classes, the base tables are still queryable without any licensed client product. The existence of a geodatabase in the RDBMS is enabled with a Server license code stored within a system table. If the geodatabase exists, and the class you wish to query is "versioned", you can still read the values (including the geometry) for any specific "version" by querying system created "versioned views". see https://desktop.arcgis.com/en/arcmap/latest/manage-data/using-sql-with-gdbs/overview-edit-versioned-data-with-sql.htm