GECKO is an R package and suite of geographical analysis functions aimed primarily at ecology and conservation science studies.
It currently incorporate easy access to SPECTRE, a novel set of standardized, high-resolution global raster layers, each a potential threat to endangered species. Check out SPECTRE at LIBRe. There you can find a handy dashboard allowing for quick visualization of each layers and instructions on alternative was of accessing SPECTRE, such as through Paituli.
As gecko is available from CRAN, you can use install.packages("terra") to get the current released version. Alteratively, install the latest release through remotes::install_github("VascoBranco/gecko").