Probably covered once before, but meh... good convo starter.
Try and limit it to like three or four and supply pics if you can.
I have a few choices that I'd import if I could.
Keeping in mind that a shield able to adapt to energy weapons would probably do jack dookie against keinetics (as evidenced by the raw damage a Bat'leth does to the Borg) I'd have two selections that would be always with me to fight them.
Morita MK 5 MI Issue Assault Rifle With it's heavy 9.8MM rapid fire AP rounds and optional under-slung Shotgun and high ammo capacity this baby in an open area would annihilate the individuality impaired.
For those pesky close quarters on a ship scenario she has a little sister.
Morita Mk5-K Officer/Pilot Issue Carbine. Lacks the shotgun but has a much higher rate of fire and ammo capacity and was used in it's home Canon of Starship Troopers as a survival weapon for Pilots and a short arm for Officers. In the CQC environment of a Cube or Sphere, this would be a rototiller.
For everyday non-use specifically against the Borg I'd have.
C-10 Canister Rifle, Ghost Op's Issue. Star Craft's Ghosts used these as their workhorse, smooth-bore 144 armor-piercing and exploding rounds that could hit up to a mile away with little or no noise and with a rifle so powerful it needs stabilizer pistons and a muzzle break to prevent the killing of it's user. Also capable of calling down strike packages (nukes included) and firing EMP and Lockdown missiles from the same barrel as it's standard ammo, these missiles are capable of even neutralizing an enemy vessel.
and last but not least at my side always.
M6SD SoCOM Pistol In it's native canon a one-hit killer and nearly perfectly silent and disturbingly accurate.
Now. How about you guys, any weapons you would want if you could have absolutely anything in game?
Godwyn Pattern Bolter. Fires a .75 caliber rocket accelerated round with a Diamantine Tip that can penetrate all but the heaviest armors. Once the round penetrates it will explode with devastating results.