None of these liquids you listed are actually peaceable in the world, and therefore would be impossible to implement as a sea. (I know that fuel comes from oil, but fuel in and of itself is not peaceable to my knowledge.)but a sea of liquid beryllium for gregtech or a sea of buildcraft-fuel is gamebreaking... and a sea of helium, methane or hydrogen is just ridiculous... because that are gases.
the forge liquid dictionary will make all liquids added to it placable in the world.None of these liquids you listed are actually peaceable in the world, and therefore would be impossible to implement as a sea. (I know that fuel comes from oil, but fuel in and of itself is not peaceable to my knowledge.)
with high enough pressure and low temperature, those are liquid. however you would be crushed under that pressureor the modders should decide themselves if their liquid should be available through mystcraft.
an eternal lavasea isn't really gamebreaking, but a sea of liquid beryllium for gregtech or a sea of buildcraft-fuel is gamebreaking... and a sea of helium, methane or hydrogen is just ridiculous... because that are gases.