Baldur's Gate 3 is famous for its dialogue, but a lot of it is hidden behind circumstances that you're unlikely to ever stumble onto. I put on my stumbling shoes and collected a few of my favorite bits of content that CAN be seen in-game, if you know how to do it.
0:00 Intro
0:28 #1 Multiprayer Game
2:55 #2 Stop, Drop, and Scroll
4:04 #3 She'll Only Seize If She Sees
8:12 #4 Background & Drowned
11:19 #5 A Tad Bit of Tadpole Talk Tonight (Setup)
15:01 (#5 Continued: Wyll)
18:23 (#5 Continued: Karlach Setup)
23:12 (#5 Continued: Karlach Speaks)
27:29 #6 Hail to the Chiefling
30:59 #7 Just Dropped In To Say Hyena
34:00 #8 Lathander? I Don't Even Know Her!