These are three of the Maxis columns as decorative objects, so that they can be placed off the grid. Four other columns like these (Mega Basic, Tintoretto, Calabria Hexagonal, Grosvenor) are available here.
They can intersect anything including walls and will automagically adapt to the wall height of the floor they are on (these are just catalogue objects pointing to the actual Maxis columns, so they behave just like these in that regard).
Note that fences will NOT automatically snap into/adapt to them, the fence is basically not aware of the deco column at all. See the “fence” screenshots for what that looks like (it’s like in TS2/3 where that fence behaviour didn’t exist either). If you need something to hide that overlap, maybe try a fencepost from one of the various Liberated fences uploads. Then again, since the ends of a fence will always be on the edge of a tile, you can just as well use the regular columns there.
Available in Build > Roof Decorations for lack of a better idea (Columns won’t work for these, as they are not actually columns) for 60§/125§/185§. Colour options are the same as for the original ones; the “Grey” colour tag on the black wood column is changed to Black.