Get a list of census fields available at the GEOID (block group) level in R

A couple of points here:

• Must use acs5 or decennial (acs1 not published to this level of detail)
• This is a table of the real world names to the internal/terse SAS names
• The total list is 21k variables, so you probably need to filter to something

library(dplyr)
library(tidycensus) 
View(
   load_variables(year="2020", dataset="acs5", cache=TRUE) 
   %>% filter(geography == "block group") 
   %>% filter(grepl('race', concept, ignore.case=TRUE)))