Inspired by this SO Q&A:

https://stackoverflow.com/q/48333523/3576984

dplyr::bind_cols syntax is appealingly clean.

cbindlist(X) would feel more data.table and provide the same functionality; even as a simple wrapper to setDT(unlist(X, recursive = FALSE)) this could be a nice convenience tool.

Not sure if there's any scope for further speedup under the hood as well.