How about crystals to 99 clusters stackable at all
jugpets to 99 petfood to 99
any food should be stackable except for things that effect a whole party.
prism powders and silent oils to 99 yes please
and just for laughs knock pebbles up to 99 as well maybe i would actually throw them for skill ups at low levels rather than dropping them.

Pretty much make anything that goes into basic crafting that is not logically bigger than a breadbox, or is consumable to 99. but that is just my 2 cents and a dream to make more space.