Act III and perhaps also Act II has some cut content. There should be a "War College" and a "Druid Tomb" somewhere in the game:
https://www.golem.de/news/larian-studios-wir-machen-kein-baldur-s-gate-4-2403-183472.html "Auch deshalb habe das Team ein paar Monate vor der Veröffentlichung einige mehr oder weniger fertige Inhalte entfernt, darunter ein Abschnitt rund um ein War College sowie ein Druidengrab."
As far as I can remember, you could also get
Mayrina's Locket as a reward during EA and she then talked about meeting at her mother's farm or at least that you would meet her mother there and I was under the assumption that her mother would then recognize Mayrina's locket.
In Act I you will also find various letters that are either addressed to NPCs in Baldur's Gate City or in which you are supposed to meet the authors there.
And don't forget the actual recipient of the Zhentarim Shipment in the Upper City, which is not available.
