I liked the bastions mine launcher, especially the 1.6 ones that either attack nearby enemies with chaining energy damage, (primary fire) or repair nearby deployables (secondary fire), but the 1.3 ones (I think) that repair (primary) and explode as secondary fire, damaging enemies, is OK too. http://firefall.gamepedia.com/Mine_Launcher
Also, maybe as a long range slow charge artillery, the Electrolaser. https://en.m.wikipedia.org/wiki/Electrolaser
Also, maybe as a long range slow charge artillery, the Electrolaser. https://en.m.wikipedia.org/wiki/Electrolaser