Old crafting materials added before Dragonflight now stack to 1,000 as of the latest Beta build. The change previously only affected Dragonflight crafting materials.
Starting in the Dragonflight pre-patch, you will save up valuable inventory space with the new Reagents bag, consumables stacking to 200 and crafting materials forming stacks of 1,000.
Previously on the Beta, only Dragonflight crafting materials would stack up to 1,000.