theres an over charged plasma rifle mk v for one of the romulan missions that is very useful
This is a really nice weapon. It has a 'random chance' factor. Sometimes it does pitiful damage. Other times it does INSANE damage. As far as the ratio goes, I'd say that it balances out to more damage than nearly every other weapon in that lvl range.
Heck, I'd say it balances out to more damage than most weapons on the next level range up... The only thing that eventually forced me to throw it down the replicator is the frustration factor.
When you get something nasty like a swordmaster flanked, exposed, blow every cooldown you have to get that awesome 2000 damage hit that will vaporize him through his ridiculous shields... EVERY. FREAKING. TIME. the thing will do about 12 damage.
The Fire Suppression Device is a mission item from “Researcher Rescue”. In the mission, it is used to put out fires on Kassae Station - but in the Season 4 update for ground combat, it can also be used to put out Plasma fires from grenades as well as the fire left behind from the science kit Geothermal vent (although it is now called something technobabbley).
2 very good, and very (unfortunately) FORGOTTEN rewards come from the Romulan Front Mission "Preemptive Strike". They are the Overcharged Plasma Sniper Rifle Mk V and the Personal Covariant Shield Mk V.
The Overcharged Plasma Sniper Rifle is a great weapon. Its normal attack is only a few damage below a Mk XII Sniper Rifle, and its special attack (the Overcharged Sniper Shot) outclasses even a Mk XII by over 100 damage. If you don't have it... You need it. I'm very surprised that it isn't more common.
The Personal Covariant Shield is exactly what it says on the tin - a Personal version of the Covariant line of Ship Shields. This means it has a high capacity (I don't exactly remember the figure), but a lower regeneration rate.
Also, while you're in the Romulan sectors, play the Romulan Featured Episodes. You get stuff like Hortas (and Attack Hortas for Crafting), Really good ship shields, and melee weapons. I recommend that you do the mission "Coliseum", the 4th Episode. That will give you Swords, Lirpas, and even Bat'Leths, without needing to even complete the mission. The glory of Melee weapons? They completely IGNORE Personal Shields.
As for ship equipment... It's all already been said.