I can confirm that Elixir of the Rapid Mind xp pot IS NOT grey in shadowlands, it is still a working item and since any xpac is 10-50 except SL being 50-60. It seems like the potion works till 50 but definitely not after 50. Great trade-off to the heirlooms since its 300% xp vs 55% but still note that these pots are no longer obtainable, whatever amount is available in the world will remain the ammount. If done right even without the pot u ca get to lvl 50 in Sl in like 4 hours if ur a speedy efficient leveler, with the pots thats