You don't need to pick up every garbage rune and gem. There will be plenty of them later on.
Also, you can cube the Arcane Shards together. After you cube 5, you'll get an Arcane Crystal, which you can use to increase the tier of items. So you could use it to improve that staff you have (if you want to uptier uniques
, you also need to add a rune with the Arcane Crystal and the item). Just make sure you don't uptier too much, or the requirements will be too high, you can check them in advance in the docs.
You'll need to come back to Tran Athulua before level 50 to do a challenge. You'd usually get a scroll informing you of this, but since you're doing p8 and clearing everything, you might overlevel before you get it. (I don't remember which act boss drops the scroll.)
lol while killing the pack wolves you said: "Let me poison every animal."