Multi-Armed and Dangerous: Well, I’ve mentioned the Eight-Legged Legion of octopus uplifts before, for a start, but even the people with humanoid morphology have received the ambidexterity and multitasking upgrades required to at least dual-wield. (A lot of the spacer clades have switched from the two-arms-two-legs model to the four-arms model, but the need to hang on to something to avoid action-reaction problems when shooting don’t make this as useful as it sounds for this purpose.
It’s still largely averted beyond that and the other naturally multi-armed species, though, because while you can – and some people do – add extra arms over and above one’s natural endowment, you can get much the same effect with even more flexibility by slaving a bunch of quasi-autonomous battle-drones to your neural interface, or occupying a swarm-bodied cybershell, which will not only let you have plenty of “arms” to fight with – just not restricted by being attached to you at one end – it’ll let you surround the enemy personally, too.