>>10479823Joytoy also makes building sets in 1:18. They're basically modular kits that you can combine together to make larger bases and dioramas. But it's all highly industrial in design, all metal plate walkways and catwalks and railings.
If you want more normal house looking buildings...I would actually look at "girl" toys and doll sets and such. I can't state any specific brands or anything, but I've come across many in scale houses and buildings that look like normal houses but fit 1:18 stuff. At worst they just need a coat of paint or something as they're all pastel colored kiddie toys covered in sticker sheets, but the sculpted details on em would probably work real well if you could do some good paint work.
You could also look into Playmobile stuff, though that might be slightly too small a scale for most stuff.