There is this spreadsheet that shows both responses and dialogue option count before the DLC 2.0, which pretty much backs up what Theosupus stated. https://docs.google.com/spreadsheets/d/1VOXnwhAVZ2bqGJgw-cgJlG0TIqt9j3zJJbRx1epH3ho/edit#gid=0
Picking out the obvious background/race/class tailored for certain story areas where it is totally relevant to your character such as Magran priest/FIre Godlike in Ashen Maw will usually let you get those unique bits though there are some like Rangers where the NPC just has to remark about your pet in the flow of conversation.
In my personal experience, I've seen quite a few of the paladins, priests, and cipher choices actively pop up while doing quests normally where many of the others are usually reactions. Also, having a caster with a decent range of spell types does bring in a variety of ways to resolve map events.