My favorite discovery is that I can use build pieces like Ashlands fort pieces for my builds and actually snap it to normal build pieces. It does require some offsetting, but it works like a charm. They cannot snap to each other, but if you make a "building skeleton" with normal wood pieces, you will be able to snap everything to "building skeleton". Once you are done, remove the skeleton and you have a build that is pure vanilla, but with pieces you cannot use normally.
This also work with fuling village pieces. They cannot snap to each other, but they all snaps to normal wood build pieces.
If you check my Mausoleum build, you will see that the most build pieces are not available at building hammer menu, but they are still vanilla.
I use VNEI mod to find prefab IDs and infinity hammer to select them. The command is "hammer [prefab ID]".