Please read the below two threads before discussing..
Things that make you go boom... https://www.sindome.org/bgbb/game-discussion/new-game-features/things-that-make-you-go-...-boom--149/
Here are the core ideas I've seen a few threads on already and a few of own.
Tear Gas: Explosives experts should be able to manufacture gas/drug grenades. For all intensive purposes, the coding for this seems to be completed - I think it just needs fine tuning. There is some discussion on this in the below link.
Cortex Bombs: I think it's a no-brainer to have cortex bomb manufactured by explosives experts with the combination of a cybernetic and explosive component.
Heavy Weapon Munitions: If we ever get to missile launchers - the ammo production should probably require explosives and munitions skills.
Bomb Vests: As it stands now, you need to hold an explosive to use it. This makes sense. I propose explosives experts be able to construct and daisychain explosives to bomb vest which allows explosives to be triggered without being held and even while grappled.
Cat's Cradle: An unconscious, sitting or otherwise restrained/grappled individual or corpse should be able to have a cat's cradle built around them. If the individual or corpse attempts to move or is forcibly moved/interacted with - it triggers the explosive.
Car Bombs: We've discussed this quite a bit and I think would help fill the gaps of a high tier explosives expert along with these other ideas. Links to prior discussions below...
Puddles of Ethanol: Containers of ethanol should be able to emptied out in rooms forming a puddle of ethanol. This would act as an ignitor and dramatically increase fire size/damage. Perfect for traps!