The goal of
this list from OSGeo is to provide basic information about all known webmapping toolkits.
There is also this
conversation about how to start web mapping.
GeoPackage is "an open, standards-based, platform-independent, portable, self-describing, compact format for transferring geospatial information. GeoPackages are databases interoperable across all enterprise and personal computing environments." Examples of implementations of the standard include: GDAL, QGIS, GeoServer.