As initially suggested by @mallrat208 here: #29 (comment)

Cyberlimbs don't do much to make them useful beyond being simple requirements for other implants.

A good and possibly thematic use of the Legs would be a bonus to knockback resistance

Arms are a little trickier as the main thing that makes sense for them could be rather over powered. I would make it a stacking bonus for both arms to encourage people to want to actively replace their secondary arm even if they have no need to.

• Attack Damage would make sense as you've replace flesh and bone with metal.
• Speed also works but is potentially stronger than a straight up damage boost.
• Increase Break Speed of Blocks depending on the number of Cyberarms

Oops, I commented in the wrong place. Ignore this.