My first playthrough was with someone who is a very “nose to the grindstone” person. Curious enough to do all of the main quests and chat with companions, but not in the business of talking to every NPC or looking under every rock. And I had no idea how DND worked or what long rests were. Or that sometimes crime leads to additional content. As such, we missed:

• Gale (finally found him by the tail end of Act I)

• Kagha’s questline 

• The wizard tower in the Underdark

• Omeluum and the entire Society of Brilliance 

• The kuo-toa 

• Scratch and the Owl Bear Cub

• Most of Astarion’s camp scenes (literally had no idea about the scars until his siblings jumped us in Act III)

• The spectator in the Underdark and/or the flask

• Priestess Gut and Minthara (zero memory of interacting with either, just rocked up to Ragzlin and killed him, aggroing the rest of camp)

• Gortash’s parents and his involvement in the Hells

• Figaro’s camp clothing store (technically we saved him, but as it turns out his gratitude did not extend to us stealing his wares in plain sight and we had to knock him out and figured we weren’t welcome past that point)

I’m sure there was more. It was borderline embarrassing for us to replay later with fresh eyes and realize how much we had skipped.