The Parking Reform Network (PRN) website on parking minimums (also called mandates) and minimums has been recently updated and enhanced. Take a look!
I have in the past worked to compile information about parking in the central city, but it turned out to be more complex that I had realized and I never completed it. It is fairly easy to map surface parking lots, that lowest common denominator of land use, but mapping parking garages is more complicated because many of them have commercial at street level, so are not all parking, and many developments have either underground or parking in the middle of the building. All of these are much harder to document and map. So I am glad that PRN, with partner Strong Towns, is mapping.
You can see the primary map at Parking Lot Map. Use the city pulldown if you don’t go directly to Sacramento. Note that this map covers just most of downtown, it does not cover the entire central city, nor any of the rest of the city. Be sure to click on the ‘View More’ button, which provide detail that is difficult to find elsewhere, including on the city’s own website.

The city’s 2021 Housing Element includes policy H-1.4: Facilitate Infill Housing Development. The City shall facilitate infill housing along commercial corridors, near employment centers, near high-frequency transit areas, and in all zones that allow residential development as a way to revitalize commercial corridors, promote walkability and increased transit ridership, and provide increased housing options . (page 23)
The implementation chapter of the housing element includes Program H8. Revisions to Parking Requirements (page 46) that is included in the PRN website. The general plan update for 2040, which would implement this program, has been delayed beyond 2022. The city has not provided a target date, so far as I know.