Use these if you want to make diamond, octagonal, or otherwise diagonal rooms in your dungeon. See screenshots 2, 3 and 4 for examples of each. (Screenshot 2 isn't a perfect diamond, but it's close; more of a rupee shape on it's side.)

I created this file by cropping a screenshot from the main ZQuest window so you could see how I have them set up as combos. I did this to avoid putting multiple instances of the same tiles so it's clear how many combos to use.
If the first combo is combo 1, please note that combo 29 is the same as the all-brick combo from the classic tileset since; I have provided it for reference of what to use there. Otherwise, all of the tiles are custom tiles.
Combos 33, 34, 37 and 38 are used as an alternate to using combos 5, 8, 21 and 24, respectively (if the first combo is combo 1).

UPDATE: I added the last four combos on the bottom for the tops of really tight corners.

The only credits go to the makers of the original classic dungeon wall tiles.

UPDATE: Blackbishop89 pointed out to me the need for the last four combos. Thanks!