Positive and Negative charges Could create electromagnets and all sorts of stuff. It may be hard and break saves but it also opens up a whole heck of a lot of new possibilities. _____
Radio active Materials over time cause other material close by to become somewhat Irradiated. This includes water and many solids. _____
Convection currents Not much to comment on this, it's self explanatory. _____
Gas bomb Type: powder It would be a fairly heavy powder that burst into a cloud of gas when it makes contact with another element. I'm not sure what gas would be best for the bomb. It would come out with a decent amount of pressure. _____
Paper Type: Solid When in contact with fire it burns When in contact with water it slowly turns to paste When in contact with various elements it stains paper Paper is normally a "background" elements What I mean is most particles can pass through it because it is "behind" them. Would not be "behind" certain elements such as diamond or walls. _____
Plastic Type:Solid or powder Would melt at a given temp but once it gets too hot it would burn away _____
Sticky Type: solid When a gas or liquid touches Sticky it sticks to it (derp). When it gets too hot or too cold it would no longer be sticky and release it's grip. When it comes in contact with water it dissolves. Maybe flammable? It would not trap them inside like some existing elements. Only on the surface.
If you are going to post something at least post something useful. I did search, but the game mechanics have changed over time so old ideas that were not possible at the time now may be completely reasonable. And since I do not know a programming language and I've not helped develop the game I don't have any way of knowing which ideas are now possible. SO I post the ones I think of indiscriminately and let the devs inform me on whether or not any of my ideas are doable or useful.
Electromagnetism is already pretty much made with Gravity now. Making things that have poles would be kind of redundant, and only limited in ways that gravity is not. It wouldn't open many possibilities, besides making it possible to separate different kinds of minerals. For which, there are already many ways of doing so.
The easiest way to make "irradiated" elements would be to make "helper elements" for each irradiated version of each element. ...Which is a lot of elements, without making a new variable or something special to delegate what's glowing green and what isn't and etc. This would be excellent work for someone's mod, but it would take up enough space on the official without really being fun to play with. I say this because, I designed a ginormous mod for wxSand off this concept. It wasn't that exciting.
Also, gas bomb can be made using breakable powered clone. Making a new element for it might be a bit silly. It -could- be neat, but then I'm not sure what it'd be useful for besides more explosions.
Liquids are basically powders that spread out. Convection movement isn't likely ever going to happen, and if it did there wouldn't be any noticable difference due to the fact that liquids which are the same density are fairly rare in the game, if any still exist. ...However, all liquids use heat convection, which means heat rises upwards faster in all liquids. Try it out. o.o
...I really can't see where Paper element is interesting, sorry. =/
Plastic has been done before, but it apparently had some unintentional game-breaking properties. Now that things have been freed up a bit, it might be doable again. I only just recently fixed the glitch with oil not turning into gas on low pressure, so stuff gets tricky.
Sticky might be neat. It could easily be done by changing a few words on the adhesion code that makes cold CLST stick and form solids without changing into another element.
I have no Idea what color Sticky would be... Maybe just white? Also I was thinking maybe if it gets too hot instead of just releasing the particles it would have the stickiness MELT off as some sort of liquid that still contains the particles (or at least the ones that don't get out when it is shifting. The remaining Element would just be diamond or metal maybe?