Datavis is where the data visualizations like charts and maps for the Council's website is kept - https://council.nyc.gov/
Templates for all the charts and graphs on the Council's website like charts on the Data Team page - https://council.nyc.gov/data/
Charts via: https://newyorkcitycouncil.github.io/datavis/templates/
Visualizations for the Agency Funding Conditions page - https://council.nyc.gov/budget/agency-funding-conditions/
Also, a hierchical json of the Adopted FY17 budget exists here
Thumbnails of the visualization templates
Visualizaitons for legislation like the Criminal Justice Reform Act - https://council.nyc.gov/legislation/criminal-justice-reform/
Visualizations about Participatory Budgeting - https://council.nyc.gov/pb/cycle-6-results/