I've been trying a variety of things that I find pretty effective in their own right, you might already know them being the LD pros you are, but I'd like to hear some so I could use too :)
I also have loadouts to share, I usually am Striker with BKC + Shadowsun Slicker and two Pentas with stats of ASI Med, DMG Ultra, and CTR Med.
Guns:
Hail Driver
Valiance
Barbarous Thorn Blade
-No one I've fought has freeze immunity, in fact, big shots that are usually a wrecking ball of terror get shut down immediately if they're frozen enough. Valiance is pretty good when you want to play safe, but I primarily used Hail in fights so I could follow up with a strong BTB slash or allow another teammate to slap them with something stronger like a Gran--Acheron. Works well in group fights as well as single fights.
Biohazard
Valiance
Barbarous Thorn Blade
-Very good at heckling and denying areas, you could keep a fight going for a long time using Bio primarily. Poison is a nice bonus and Valiance is the great finisher. BTB can be used in conjunction with Bio very well due to many orbs denying movement. Does very poorly against Snarbolax and Shadowsun users, but works well in group and single fights otherwise.
Sentenza (Would be Carbine if Radiants existed)
Argent Peacemaker
Barbarous Thorn Blade
-Absolute best guns for harassment...side Polaris. Been called "Sentenza/AP" spammer on occasion when successful with kills and screwing up their attack rhythms. Although I'm a one trick pony having two of the same guns, I was able to exploit enemy's defense choices to perform "massive damage". The trick I usually use is to stop their movement with either gun then when they stumble towards me, I slash with BTB and go back to long distance shooting until they either decide to flee or try again. This works best in single fights, but wouldn't perform badly against an extra enemy focused on you. It's best to avoid group fights since it is easy to be shut down if you miss your shots, but if you have godly aim, you can be next to invincible anywhere. I think I like this best.
So what weapons do you like to use in particular and how do you use them? :)
Lots!
I'm most comfortable with Carbine Biohazard and Flourish with a BKC Shadowsun and two pentas. Even those with shadow armor suffer from hitstun and poison which can set them up bigtime.
I make like 5 different loadouts a day before heading in to LD. Variety is the spice of life!