What places/landmarks/npcs/… did you come across that were in previous Diablo games?
I found the hidden camp from D3 act 2 the other day. Which was a nice find, since unexpected.
location
directly north of the Denshar WP, east of Gea Kul
story related finds
…and obviously Lorath as well as old Meshif from Lut Golein in D2
Caldeum is a pretty major part out the D3 story, and returns in 4 as a burnt out ruin ingested by cultists and demons.
The leader of the town of Backwater is the scoundrel helper from D3. Same VA, too.
Supposedly there’s a quest I did that (at the time I didn’t realize) was about what happens to the Paladin from D2?