Track whatever missing buffs you want to track via spellID and display them in the same place as your existing buffs.
Track whatever buffs are low duration (longer than 1min buff, less than 4min (configurable) left)
Track missing weapon effects (oils, sharpening stones, poisons, etc) via enchantID
You will need the buff spellID and not necessarily the spellID of the cast spell. On wowhead this will usually be the green text link of the parent spell. You can also add things like mana potions by adding the spellID but keep in mind that these will have that dude's face as an icon until you have a mana potion in your inventory.
You will likely need to configure group scale/position to match your UI. Also feel free to make copies of the class auras for different specs. You can use these as settings backups for future versions.
Support more aura development! http://buymeacoffee.com/darpeh