There are many different categories of New York City Property Tax Exemptions. There were extracted from the property tax bills by our friends at http://taxbills.nyc Here is a list of the many special property tax exemption categories: https://taxhistory.brooklyncoop.org/view_show.html?type=starttaxbills_exemption_types.json There are 206 categories. Here is a breakdown by year: https://taxhistory.brooklyncoop.org/view_show.html?type=starttaxbills_exemption_types_history.json key 1 1-2 family dwelling 2 1-2 family dwelling - 421b 3 420c housing 4 421a (10 yr cap) 5 421a (15 yr cap) 6 421a (15 yr not cap) 7 421a (20 yr not cap 8 421a (25 yr not cap 9 421b (1-2 family) 10 5.0230% 11 7.1120% 12 a.l.,vfw,cwv,jwv,etc 13 academy of music 14 airfield 15 airfield -do not use 16 alteration 17 amtrak (fed subsi rr 18 armed forces 19 armory 20 basic star - school tax relief 21 basic star - school tax relief 1 22 battery park auth 23 bd higher ed (cuny) 24...