I'm going through the authors in alphabetical order, adding a levels.nxmi to each folder. I'm having to do this in short bursts as it's extremely tedious, but we'll get there.
From Clam's folder, I am removing levels that also appear in Clammings (https://www.lemmingsforums.net/index.php?topic=3642.0) (mobius's new-formats compilation of Clam's levels from various sources). For some of these levels, the version in Nepster's compilation may be different from mobius's version, so I won't delete these levels -- I'll just move them to a separate folder that won't officially be part of this pack.
Hello, Goodbye
Lemming Recycling Plant
FALL AND DIE
Dig This!
Catch Your Death
Leaky Building Syndrome
Rounds and Swingabouts
Escape from Alcatraz!
Bumpy Ride II
The Christmas Rush
Times Four (circular clicking)
Get Out of the Pool!
Go Fetch!
A.T. on an Angle
Barrel o' Laughs
RABBIX II
Who lives... and who dies
Crevasse
Turning the Screws
Nothing to lose
The Other Side
Lem ramp scam
The Dying Seconds
Flotilla
Empty Apartment
Builders' Cracks
Mont Blanc Tunnel
Training Zone Alpha
From the Brink
The Floodgates Open
A step too far?
MORE WEE CREATURES
Play Bridge
Works on so many levels...
The endless steps
Lem Squared
Altitude Training
Fill the floor
Circus lemmings in training
Guns Blazing
Spiralling Snowstorm
I have not removed "The Square Route of Lemmings" since the two versions are different enough to be considered separate levels with the same title. (This may apply to some levels where I haven't noticed it, so if anyone knows of any, feel free to point them out.)
Nepster's compilation contains "Bumpy Ride" and "Bumpy Ride II", where the second one is in Clammings but is simply called "Bumpy Ride" there, so I have removed the duplicated level and kept the other one. The same applies to the "RABBIX" pair of levels.
Insane Steve's levels will need similar treatment.