Fantasy Castle Architecture Pack by Mincsims
I looked at the Castle kit EA put out and it was missing a few things that I had wanted from a castle pack-- obviously it's just a kit so it doesn't have a ton of content. I particularly missed windows without glass. Specifically the arrow slit windows. I was searching for Sims 4 arrow slit windows and this came up:
https://www.modcollective.gg/sims4/details/collection/4753
The Mod Collective is a bit of a pain to navigate, requires registration, and limits how many things you can download at once and has an hourly limit. However, it does have some very cool stuff.
This set includes friezes, corbels, crenellations, walls, arrow slit windows, and portcullis.
It was uploaded Oct 29th so it is relatively new.
If anyone else knows of some good castle cc, please let me know. I'm still hoping for some machicolations.
I'd love to get some see-through grates like the ones on these machicolations:
I'd also be fine with square or rectangle wire grates-- just something to stop people from falling through.