The CHELSA climate dataset is pretty great. This R library has some simple utilities for downloading batches of CHELSA data from within R, and for parsing the names of CHELSA files to identify key metadata variables like GCM names and emissions scenarios.
ch_queries(variables = c("temp", "prec"), models = "ACCESS1-0",
scenarios = c("rcp45", "rcp85"), timeframes = "2061-2080",
layers = 1:12) %>%
ch_dl()