Weapons, that may inflict sleep
Hypnotizer series.
Bomb like other vaporizers makes first weak explosions & cloud, that leaves several seconds & cast debuff (in this case - sleep). Unlike other vaporizers it deals shadow, & not elemental damage.
Haze bomb -> Hypnotizer -> Hypnotizer mk2 -> Hypnotic atomizer
Hypnotizer:
10x green shard
3x ecto drop
2x gel core
1x zee core
Hypnotizer mk2:
15x green shard
4x ecto drop
3x gel core
2x zee core
1x cursed idol
Hypnotic atomizer:
20x green shard
5x ecto drop
4x gel core
3x zee core
2x cursed idol
1x philoso feather
Somnotech alchemer series.
It's mere alchemer like gun, that deals same amount of shadow damage, as vol(cryo/firo)tech deals elemental damage. It forked from shadowtech alchemer.
Shadowtech alchemer -> Somnotech alchemer -> Somnotech alchemer mk2 -> Somno driver
Somnotech alchemer:
10x green shard
3x scrap metal
2x gremlin gizmo
1x zee core
Somnotech alchemer mk2:
15x green shard
4x scrap metal
3x gremlin gizmo
1x force dynamo
1x zee core
1x silver coil
Somno driver:
20x green shard
5x scrap metal
4x gremlin gizmo
2x force dynamo
1x zee core
2x silver coil
1x plasma cell
P.S.: i very want this weapon.

Sleep is not balanced when used against knights.
Until that is resolved none of this is useful.

I hope the Devs do something really good with sleep, because right now it's completely useless.

The sleep effect wears off if any damage is dealt. Therefore, these weapons would be messed up in their own world, the damage destroying the sleep effect.

There is really no point in adding a sleep weapon. Wouldn't be very useful
However, FREEZE status also wears off when enemy get hitted. Meanwhile, it's useful and many wields shivermist buster for inflicting it. Likewise sleep wears off NOT when enemy hit with shot trying to apply debuff, but first enemy hitted, second trying to apply debuff. Sleep durability much more than freeze & enemy can't shield/attack straight/heal (gremlin mendor case). Paid for this is absence of final damage & slight heal (must be significally nerfed not more than 10-20 pts per second it stratum 6).
Also: maybe remove sleep heal completely, instead this make status removeable by near shooting/hitting/exploding e.t.c. (cuz noise).

Looks interesting, but needs more detail:
- What kind of monsters are going to drop the material Cursed Idol?
- Sleep is currently bugged due to its ability to heal knights and monsters - once resulted in people walking into Sloombargo mist for healing. You may wish to put the way you plan to work around this in the OP.
- Are you planning to reintroduce Slooms to the game, since they no longer exist (not even in monster cages)?
Also, you may want to change the shard type used to Dark Shard instead of Green. It's a petty detail, but since the weapon inflicts Sleep and the gun deals Shadow damage it would make sense for it to have that shard type.
Crushion series.
Crushion is weapon, that works quite as troika & its derived sword. It's most likely heavy swords, that copies their attack. However, it can't stun enemies with charged attack, instead it final explosion not damages targets, but has fair chance to soporify enemies. It can also inflict sleep with regular attack. It deals normal-type damage, but significally weaker than troika-series. Also it not derived from it & independent weapon line.
Pleasant Crushion -> Very Soft Crushion -> Extremely Gentle Crushion
Pleasant Crushion:
10x green shard
3x gel drop
2x owlite feather
1x fine fabric
Very Soft Crushion:
15x green shard
4x gel drop
3x owlite feather
2x zee core
1x miracloth
Extremely Gentle Crushion:
20x green shard
5x gel drop
4x frayed fabric
3x bushy tail
2x cursed idol
1x silverweave
Slooms drop zee core, they drops cursed idol too. In general they going to drop:
Green shard,
Light shard,
Gel drop,
Gel core,
Zee core,
Cursed idol,
Royal core.
Yeah, we need, reintroduce it. We removed it because there'sn't item, crafting of what consumed zee cores. In some items (jelly set, iron plate set) there's sleep-resistance scale, but FOR WHAT it if there'sn't monsters that can lull, also no weapons can lull, in even lockdown there'sn't sleep vials. Also i want reintroduce tortodrones as heavy enemy in arenas "Robo Rampage" & "Wrench Warfare", cuz current monsters are not suitable for interior.
Also i've next idea - maybe make sleeping enemies to possible to lift & throw like ember/water balls. Not possible to lift and/or throw heavy enemies like lumbers & alpha wolvers. If it pushes other enemy both will affect some normal-type damage, if was thrown in wall, same quantity, but damaged only thrown enemy. If it was thrown into abyss (but not through it) - it disappears completely without dropping any loot.

Man... this is harder to read than luiguru's balancing pages
Maybe better change name from "pillow" to "crushion" (crush+cushion)
Zee cores drop from slooms, which are common for shadow lair mk2 jelly palace (sleep themed). Cursed idols, imho will may be traded for 2 almirian seal from token trader (cuz this seals are dead cargo for cycling FCS players, while items from it practically can't be traded), likewise rock salt.

Sleep is still not balanced.
None of this is worth a drip of snot until that is resolved.
Sorry to rain on your parade but I believe the Developers have something already planned with Sleep. Derrrrrp.