We already have helium (NBLE is helium) now I think we should add it's opposite, sulfur hexafluoride.  Also I have a new toggleable engine suggestion that will allow us to simulate greenhouse gasses in tpt.  Here are the suggestions:

Greenhouse gasses:

It's a toggleable engine like ambient heat and newtonian gravity.  When it and ambient heat are both turned on, CO2, WTRV, GAS, and SFHX(see below) conduct heat to empty space like most other elements, but unlike other elements their temperature does not lower (but can still raise) when doing so and they only conduct to empty space, not from it.  Ambient heat created by them (while Greenhouse gasses is on) won't lower the temperature of any element hotter than them, this is to avoid LAVA being cooled down by them because, realistically, magma in volcanoes is not cooled down by climate change.  What all this means is that every thermally conductive element in tpt that is of a lower temperature than these gasses will be heated up to their temperature.  These gasses will retain their heat conductivity so the ambient heat they produce will heat up elements at the same speed as the gasses themselves would if touching the elements in question directly.

Sulfur hexafluoride (or SFHX):

SFHX is a non-flammable gas that is the same color as HEAC, and the first tpt element to have the leter X in it.  It has the same heat conductivity as HEAC and the same electricity-blocking properties as INSL, i.e. one pixel of SFHX can block a SPRK like one pixel of INSL can.  SFHX can also block SPRK(ETRD) from "jumping" to a specific pixel of ETRD if it is in any point that's in between the two ETRD pixels, not just in the center pixel like with INSL.  Because SFHX's temperature can't be lowered (but can still be raised) when Greenhouse gasses(see above) is on and because it instantly conducts heat like HEAC, all thermally-conductive elements below it's temperature (except the other greenhouse gasses mentioned above) will instanlly be the same temperature as it is if Greenhouse gasses and Ambient heat are both on.  It moves downward at twice the speed as CO2 and unlike other gasses, which spread out with or without an external force, it stays focused, i.e. it stays in the same x coord as it falls down.  This is similar to DMG, which also stays focused as it falls, unlike other powders which spread out as they fall.  Obviously, it will move to a different x coord if pushed by pressure, PSTN, or some other external force.  This "don't spread out" property is, as you know, unique among tpt gasses and it means that SFHX is the only gas in tpt that can be affected (at least properly) by ACEL, albeit vertically and not horizontally, as it does not move randomly like other gasses.  It's also heavy enough sink below MERC and even FWRK, making it the heaviest element in tpt; solids don't count because they don't, normally, move nevermind fall.  Molten STNE, molten BRCK, and molten ROCK turn into molten HEAC upon contact with it.  The resulting molten HEAC, as you know, cannot be turned back into molten HEAC once solidified except by by LIGH.

@username90000 (View Post)

 We DO have helium, NBLE is helium not neon.  HYGN fuses into NBLE in tpt and hydrogen fuses into helium, not neon, in real life.

Enough about NBLE, what do you think of SFHX?