You can use the MOD13Q1 products for Terra and Aqua, the NDVI is available for 16-Day for both of them (i.e., max 8-Day delay). See the bellow link (GEE):
Christophe Bocquet please go through this link. I hope this may be useful. https://lpdaac.usgs.gov/dataset_discovery/modis/modis_products_table/mod13q1_v006