Oh, boy... There's so much ! Smokeless Image has Clearomizers... which are 1ml & use a different method of delivering vapor...
Inside the cartomizers is a filler that is soaked in e-liquid, but the clearomizers are clear & you can actually see how much liquid is in them - they use a wicking system, meaning that there are wicks inside & two tiny holes at the bottom, through which the liquid is slowly absorbed through, see below :
View attachment 173004
They also carry the CE3's - they are also clear, as you can see, but they have to be filled with a syringe :
View attachment 173003
They also have other juice delivery systems - but they are wider in diameter. These fill be flush with your cigarette style batteries.
I can tell you about them also, if you want - or are considering buying the X2 battery or the Spinner =)