Flash the names of workspaces name when switching to them. This is a reimplementation of XMonad.Layout.ShowWName as a logHook.

You can use this module with the following in your xmonad.hs:

import XMonad.Hooks.ShowWName

main :: IO ()
main = xmonad $ def
  { logHook = showWNameLogHook def
  }

Whenever a workspace gains focus, the above logHook will flash its name. You can customise the duration of the flash, as well as colours by customising the SWNConfig argument that showWNameLogHook takes.

Alternatively, you can also bind flashName to a key and manually invoke it when you want to know which workspace you are on.