Thought up of some tileset ideas, considering that lots of graphic sets have been released ever since NeoLemmix came out:
Race Track - cars as terrain as well as roads, slopes, cones. Tires, pit stops.
Bank - lots of money dollar bills, gold coins, silver coins, bronze coins. The exit is a bank vault, and can also serve as a locked exit - you just need to collect all the keys.
Kitchen - cabinets, blenders, stoves, refrigerators. A refrigerator trap where it freezes the lemming, a microwave trap where the lemming gets cooked.
Bathroom - sink, toilet, bathtub. Soaps, rubber ducks, sponges, loofahs. The toilet is a trap, a lemming falls inside it and gets flushed. The hairdryer can also be a fire trap.
Casino - poker chips, cards, slot machines, backgammon boards and billiard boards.
Oz - a yellow brick road, lots of castle bricks, emeralds, and of course the ruby slippers. A trap where a house falls on a lemming, much like how the Wicked Witch of the East gets crushed by the house.
Time - expanding on Minim's idea, clock hands, grandfather clocks, numbers. I know there's a Clockwork graphic set, but this is different in that there are actual clocks. Also, watches, digital clocks, perhaps a TARDIS as the exit (we have one in the L2 Shadow tileset).
City - not the Route 99 city seen in Lemmings Reunion. An actual city, with buildings, all kinds of transportation. Traffic lights, highways, pylons, and also construction.
Harbor - lots of boardwalks and ships, with one ship serving as an exit.
Windows Desktop - lemmings roaming around a Windows Desktop. The exit is a "NeoLemmix.exe" program. Start menu, desktop shortcuts. The Recycle Bin is a trap.
Chalkboard - lemmings on a school drawing board. You can make all kinds of drawing with the differing colors of chalk. This graphic set can give you a good nostalgia trip back to the preschool days and you drew lots of fun stuff on the board.
Castle - not the one from Nicky Boum (PimoLems, Lemmings Reunion), but a medieval castle made from scratch. The portcullis is the exit.
Dungeon - also has a portcullis exit. Prison bars, maybe even skeletons. Lots of slime, and chains, handcuffs.
Playground - you've got all kinds of equipment - slides, climbing monkey bars, ladders, swings, see-saw, merry-go-rounds. The see-saw can be a trap that flings the lemming into the sky, while the merry-go-round that spins fast can be a fire object.
Library - lots of bookshelves and staircases. A single-use trap can involve a bookshelf falling on a lemming.
Moon - we've got a Martian graphic set. Why not a graphic set that takes place on another planet, especially if it's one that is so much closer to Earth? Make sure to include Neil Armstrong's footprint as well! A single-use trap can be a lemming entering a rocket, but then the rocket blasts into space.
Ruins - lots of wall structures, maybe Macchu Picchu-type ruins. The exit can be of a rock head and mouth, and a locked exit can involve the exit's mouth opening. Boulders are traps, rubble falling on lemmings and forever burying them is single-use trap.
Orange - lots of orange-colored terrain. We can also add fruit oranges and orange juice. namida once considered this idea for LPII.
Labyrinth Zone - A really nice water ruins graphic set, with spears as traps, fireballs, spikes, and lemmings drowning in water. The smooth edges of the ruins are very easy to make hard levels with. The Scrap Brain version of the Labyrinth Zone should also be included.
Three Pigs - a graphic set of straws, sticks and bricks. The wolf is a trap that blows the lemming away. Though I guess this can already be achieved by mixing graphic sets, the sticks in the Rock graphic set and the bricks in the Brick Graphic set...but what about straw?
Farm - barns, hay, straws, and lots of farm animals - cows, pigs, ducks, and eggs.
Eggs - unhatched eggs, egg yolks, scrambled eggs, easter eggs, you name it!. This tile will also call for some eggstremely eggselent egg puns as level titles
.
Easter - easter eggs as unlock buttons. You have to collect all the eggs in order for the exit (a rabbit hole) to open.
Scarlet - why not turn those red squares in Nepster's A Study In Scarlet into an actual graphic set?
AWESOME - we are way overdue for an actual tileset based on What an AWESOME Level. Traps include more AWESOME worms that eat lemmings, wormholes as teleporters, spaceships. The exit can also be one of the AWESOME worms. Include
these sprites as well. Proxima's
Cheapo version of the tiles is a very good starting point for those who want to make the tileset.
Math - lots of math tools. Calculators, rulers, triangle rulers, compasses. Numbers, equations, and lines and circles, all kinds of shapes.
Waffle - a graphic set made of...waffles. With syrup.