Security guards outside the Heidekker offices are seen with holstered SIG-Sauer P226's in "Nosedive" (S03E01). An airport security guard (Abubakar Salim) is briefly seen with what also appears to be a P226 in a blue Roni Pistol Carbine Conversion in the same episode. Medina (Sarah Snook) is seen with what appears to be a holstered P226 in "Men Against Fire" (S03E05).
Unknown Pistol
An airport security guard (Abubakar Salim) is briefly with an unknown holstered pistol in "Nosedive" (S03E01).
London Metropolitan Police SC019 officers are seen with holstered Glock 17's in "Hated in the Nation" (S03E06)
Assault Rifles
FN SCAR-L
In "Men Against Fire" (S03E05) several soldiers including Stripe (Malachi Kirby), Raiman (Madeline Brewer), Medina (Sarah Snook) and Lennard (Kola Bokinni) use FN SCAR-L rifles fitted with EOTech sights, AN/PEQ-15 laser sights, and FN Mk 13 Mod 0 grenade launchers. Though not visually modified, the rifles appear to be intended as a futuristic design, as the gunshot report includes that of a fictional laser or pulse round.
A soldier is briefly seen carrying an FN F2000 in "Men Against Fire"(S3E5).
Colt M4A1
Colt M4A1 carbines are seen carried by London Metropolitan Police SC019 officers in "Hated in the Nation"(S3E6).
Rifles
Unknown Bolt Action Rifle
In "Men Against Fire"(S3E5), a Roach is briefly seen with an unidentified bolt action rifle, which it uses to shoot down a military drone.
Grenade Launchers
FN Mk 13 Mod 0
Several Mk 13 Mod 0 grenade launchers appear in "Men Against Fire"(S3E5), mounted on the soldiers' FN SCAR-L rifles. Lennard (Kola Bokinni) is seen using one to fire a futuristic device that provides a holographic layout of the surrounding area. Medina (Sarah Snook) refers to it as "the boomer."
Other
X26 Taser
Several London Metropolitan Police officers are seen carrying holstered X26 Taser's in "Hated in the Nation" (S03E06).