Viridis, now the matplotlib default, is quite popular:
* https://bids.github.io/colormap/
* https://cran.r-project.org/web/packages/viridis/vignettes/in...
Google recently introduced an improvement on the venerable "jet" colormap called Turbo: https://ai.googleblog.com/2019/08/turbo-improved-rainbow-col...