I like the jar cuz it hits like a truck and has decent ammo. The scorcher fills a similar niche in that it kills all the same targets in similar times, it just doesn't have as much ammo per mag.
I second the crossbow, beautiful gun in terms of performance. I just find it a little underwhelming to actually use, it doesn't have the visceral satisfaction of the other guns, it's lacking the bang and immediate feedback I think. Great effect on target though and can kill fabricators which is super handy.
The diligence counter sniper is a good head popper if you can manage the accuracy needed to be effective with it.
I always enjoyed the slugger for the stopping power and stagger. Doesn't do the walkers very well though compared to the others.
If you have the dagger try it against the bots, I really appreciate it for being able to shoot berserkers whilst running away and being able to pop mines without wasting ammo. It's surprisingly useful to have an infinite ammo secondary against the bots.
The scythe the continuous fire laser is pretty bad, it got a buff recently which makes it barely useable. The sickle the assault rifle laser is pretty good and quite satisfying to use.
The dagger got buffed in the big patch and works pretty well now rather than tickling everything.
The other energy weapons worth using is the blitzer shotgun but only on the bugs and the plasma shotgun which has so much stagger it's good for both.