I think a cool weapon type would be charge weapons! These charge weapons may have a new category, or just be an option in stats. The "charge" stat would determine how many turns you need to spend charging the gun to be able to fire it.
Here are some examples:

Charge Gun
85 electric dmg
-12 energy dmg
1 charge
2-3 range

Overcharge
120 electric dmg
-25 energy dmg
2 charge
3-4 range

Power Trident
50-150 phys dmg
1 charge
3 uses
3 range

Sneaker Wave
100 phys dmg
3 charge
1 use
3 knockback
2-5 range

Omega Laser
200 explosive dmg
+50 heat dmg
3 charge
1 use
3-5 range

What do you think?

the last one is waaaay OP