Firstly, I think that there should be more explosives. What I find fun about TPT is the fact that if you get bored of something, you can blow it up! And if people get a wider array of explosives, it would be so much more fun! Secondly, I think that plasma should be moved into explosives because it's basically more powerful fire.
TNGN - Tetranitrogen is an extremely explosive gas, releasing immense amounts of heat and pressure when it explodes.
ANFO - Ammonium nitrate and fuel oil; this is not detonated by pressure/shock
STAZ - Silicon Tetraazide is a highly unstable chemical that can spontaneously combust unless it is in a solution.
SZAQ - Silicon Tetraazide Aqueous solution is much more stable and can be used in explosive applications
Have fun adding precursor elements to those and finding more explosives along the way.