National Spatial Planning Data Repository (NSPDR) portal covers a large variety of spatial data incl. admin boundaries, agriculture, hydrology, infrastructure, environment and properties. Municipalities also load their own data on the portal so there are some niche data sets for specific areas.
CDNGI Geospatial Portal has a comprehensive mix of spatial data
Provinces and cities
The Gauteng Integrated Geospatial Data Platform hosts data on themes ranging from human settlements to health services, education and available land
Administrative boundaries: Municipal Demarcation Board (MDB) boundaries which define provincial, municipality and ward boundaries. All files can be accessed on the MDB data portal. Also access MDB, 'main place' and 'subplace' information - similar to suburb - as Shapefiles on SA-Maps (which come from Stats SA).
Postal codes: The postal codes define regions that are used by the Post Office for delivery of parcels, although they don't seem to correspond to other boundaries very clearly. The postal code lists can be downloaded here.
Surveyed land/ cadastral information: Most land (usually termed a township, allotment, holding, parcel, portion, erf and/or farm amongst others) in South Africa is surveyed to define the boundaries of the land - referred to as cadastral information. It must be surveyed before it is subdivided or sold and registered in the deeds office. When surveyed and included in the spatial cadastral database by the Chief Surveyor General (CSG) Office, the land is assigned a unique alphanumeric key explained here. Cadastral information can be viewed on the newish CSG data viewer. The CDNGI Geospatial Portal is a good place to go for various spatial data.
Title deeds: The ownership of land (or more broadly property) is largely governed by title deeds, which specify who the owner is - whether a private, individual person, trust, tribal authority, company or state entity. Deeds information can be requested by registering as a user on DeedsWeb, via DeedsView, on the CSG property search, or through a private provider like Windeed. The Phase 1 State Land Audit Dataset for eThekwini Region can be accessed here and for the Northern Cape. These datasets contain over 140,000 records for registered State-owned (government department, municipality and similar) land in these two areas.
Valuation roll: The valuation roll for an area is largely based on cadastral and deeds information, along with valuation of the properties which is done by the municipalities themselves ('municipal valuer'), to calculate the rates that landlords must pay for municipal services. These valuation rolls are typically public, e.g.: eThekwini, Sol Plaatje, Polokwane, Cape Town, Johannesburg.
Land use and capabilities: The South African Land Observatory data can be accessed here and provides information on land use and land capabilities [Currently not serving data]. Rather look at DEA's E-GIS for land cover and land use data, SANBI for biodiversity information, and some datasets from DAFF such as grazing capacity. The CDNGI Geospatial Portal includes land use and land cover data. This site also has SA national land use/ cover data.
Health: See all the health service and facilities location data on this page.
Social grants: Post office locations can be accessed here (available as separate SAPO and RPA datasets) and SASSA service points through a map view here, or as a dataset with latitude/ longitude of service points.
Travel: To see what people's travel patterns are like (origin-destination, duration, etc), you can access micro-data from the 2013 National Household Travel Survey on Datafirst (registration required), as well as this extract on travel to places of study. Metrorail timetables and maps are buried in pdfs. And airport arrival and departure statistics over multiple years are available in pdfs too from ACSA here (see below for more transport related infrastructure data).
Housing market: Have a look at the Centre for Affordable Housing Finance in Africa dashboards. StatsSA publishes an interesting annual report on private sector building statistics, based on submissions from municipalities.
Settlement planning and construction: The Housing Development Agency hosts a variety of dashboards through LaPsis including the municipal profile viewer, primarily for Northern Cape and North West municipalities. The ismaps tool explores the upgrade potential of informal settlements in Cape Town. For checking construction companies and builders, users can submit information on the NHBRC registration verification tool.
Estate agents: The Estate Agency Affairs Board (EAAB) list of agents including registration status.
Evictions: This new guide provides useful information on eviction laws and rights.
DAFF happens to have datasets on roads and airports from the late 1990s. But you can also get regularly updated open roads and rail data from OpenStreetMap here as pbf or Shapefile, or via this server. Globally crowdsourced airport data can be accessed from OurAirports as csv file.
The more official NGI data can be accessed from SASDI by searching for "Topographical Vector Data" in the list view, then downloading the zipped Shapefile for your Province.
The CDNGI Geospatial Portal includes transport-related data.
The energy sector is diversifying and changing relatively quickly, so it's interesting to visualise what's happening in the renewable energy space. DEA publishes datasets, such as this one from Q2 2018 [currently being migrated], on location and capacity of renewable energy project approvals, renewable energy development zones and transmission corridors; DOE shares information on location and capacity of renewable energy projects through REDIS (example dataset from July 2018); and you can get wind energy data here.
Eskom publishes plans for the transmission network as a Shapefile which includes location of existing and future substations and transmission lines.
More detailed data on electricity transmission is available on the Bioenergy Atlas, which also has data on biomass availability amongst others.
The National Energy Regulatory of South Africa (NERSA) posts regulatory decisions and licenses in PDFs, but many of these have been harvested and also available on the Bioenergy Atlas.
See a dedicated page on water here.
The most interesting spatial perspective on economic activity is from StepSA, and the dataset updated in 2018. Otherwise, private data providers like Quantec and IHS Markit use StatsSA and other data sources to estimate activity down to the local municipality (and possibly even ward?) level.