Two D3D scrapped sector effectors
Decided to experiment with these a bit.
At least these two effects exist in the LD code that don't exist in the final version, there might even be more.
While these are useless now, it still interesting to see what different ideas they had in mind before overwriting these slots with other stuff.
SE 18 - Vacuum, Similar to the one seen in various videos.
When paired with a typical SE15 sliding door, the point where the SE is at will be the source of the vacuum.
This will drag all in various enemies and other objects such as explosion sprites.
SE 23 - Flooding sector

A rather buggy effect that changes a dry sector to divable water while flooding it to a set height.
-> Diving itself works the same as normal SE7 underwater transport.
-> As a side effect, Sector #0 gets lowered to the same height as the bottom of the dry pool.
-> Flooding process starts once the player gets in the sector.
-> Biggest bug is that the underwater sector also has it's floor texture changed in to a water texture but it's not divable.
Create an empty pool, this will be the flooding sector. This can be split in to as many child sectors as you wish.
Create the underwater section of the pool, same as above, you are free to split this one.
Link these in a typical SE7 water transport fashion.
Unlike a typical divable water, the top side must be dry and lowered to the same height as the bottom of the underwater sector for the least glitchy outcome.
Now every affected sector that is over or under water has to have the same hitag.
Create a single SE 23 sprite that will determine the height that the water will rise in to on the dry pool sector.
For reference:
Dry sector -
Dry sector in editor -
Underwater sector
- - --
There are other effects that got unused in the final game but actually exist in some of the maps in lameduke so you get to see them in their "natural habitat"

I suggest reading the URL for more information.
SE26 - Escalator
A rather buggy effect that raises and moves a single child sector in a certain direction before resetting it's position instantly. Having multiple of these chained gives the illusion of moving escalator steps.
Seen in E1L5 on LD.
SE5 - "Boss creature" / helicopter
Another effect that is pretty buggy but gets used on E1L7 and E1L8 maps in lameduke.
While infosuite refers it to as the turret, it's obvious what it was meant to be.
SE19 - Airlock windows
Makes the sector go shut (from top) if it detects that a glass was broken inside it. One of the videos suggested that it was combined with the vacuum at one point, possibly the room would have that applied until it got fully shut.
This gets used in E1L1 of LD.
Found another one, as far as I know, this is unused even in LD levels.
SE16 - Rotate reactor sector
This combines two main effects:
1) Piston, once the level starts it will lower the roof of the sector to floor level.
The piston will start moving up and will remain at the roof level unless there is another (any) sprite in the same sector.
Movement speed is slightly faster when the piston goes down and slower when it goes up.
2) It applies rotation to the sector, which is the usual rotation. What makes this different is that this SE also acts as a pivot sprite.
In the end this combines roughly 3 different SEs in to one, along with the variable speed for directions which is not really seen elsewhere.
- This effect works with retail AND lameduke, the main difference is that the retail version accepts only the reactor sprite inside it before it starts working.
once the reactor is destroyed (or the placed sprite in LD), the effect halts. I guess the requirement was changed as in LD you can stop it quite easily with just generic projectiles.
Strict requirements might be why it isn't that well documented. Still quite a lot of potential applications!
I think that is all that LD offers when it comes to SEs, roughly around 26 there seems to be nothing above it.