I don't know to what extent the details are needed, but these are gaps I see currently:
And these are just generic ideas, I could discuss in some more detail how this could fit into SD's setting, and I'd be willing to write/work on the requisite lore and messaging, if applicable.
-A wrist-blade / Mantis blade / Telescoping long blade for sword users.
-Similarly, a subdermal katar or punching blade for martial artists.
-Dermal Plating specialized for impact/projectile defense. Maybe tweaking dermal to provide better defense against other forms of damage in lieu of new dermals getting added.
-Drug auto-injectors. Load your favorite candy into a cartridge and be able to pump it as a free action in combat - note - this would only apply to the loaded candy.
-Non-nanogenic parity for existing nanogenic functions. Myomer muscle grafts, Hardwired Reflexes/Wires, synthetic blood, coagulin pump, etc. Basically, cheaper alternatives to nanogenics that might come with a slightly higher PDS load and be rippable. They'd also have no lag time on installation to getting a stats boost, and would likely be visible to some degree (unnaturally bulging muscles, fine silver-like filaments in the skin, off-color veins, etc.
-A perception boosting chip to augment existing eye/ear chrome.
-An upgraded skillsoft Mk.2 that's more suitable for using with combat-related skillsofts (this is a woefully untapped resource just begging to be used!) Yes, it comes with a socket cover and lock.
-Wireless scrambler implant. This would have to be pretty expensive and/or only usable for a limited duration. Once triggered, it couldn't be manually turned off, and maybe alerts nearby locations with some kind of tell that something's up. Static on SIC, garbled messaging, etc. This could also disrupt wireless camera transmissions, which would potentially give it a ton of alternative non-combat uses.
-BullyStopper9K: A set of insulated electrodes around your neck that can fry people attempting to choke you out. Might look like a collar or choker of some form when installed. Relatively cheap, and probably requiring a battox and time between uses. Essentially a one use get-out-of-jail-free card to prevent people with a significant statistical advantage on you from choking you out or dragging you around. Would leave your assailant temporarily stunned for a few seconds, and probably with a nice burn on their arms.
-CyberHeart: Exhaustion is a thing of the past. Replace your meat heart with a continuous-flow pump. Functionally identical to your normal heart under most circumstances, it really shines when an external gel-cel is attached, allowing the user's heart to run wide-open without causing rapid exhaustion. Power draw is high during this time, and a fully-charged gel-cel is only rated for a few minutes at maximum output. It's also not a simple task to place a fresh battery in the chest port, and would not be advisable in combat situations.
-Carbon Fiber Bonelace: Leverage the power of modern materials to upgrade that stone-age skeleton. Laugh in the face of falls that'd break lesser chums with both weight savings to help lessen the impact, as well as the incredible strength of carbon materials to distribute the shocks. Bonelacing effectively allows you to make risky jumps with some level of certainty that you're not going to simply splat when you land.
-SK AutoMed 8K: Take the supplies from commonly-found medical kits and slot them into your AutoMed™ ports, and relax, knowing that AutoMed™ will work around the clock to make sure you're healing at the fastest rate possible. Are you a paragon of physical health and training? Then let the AutoMed™ 8000 get YOU back into the fight - faster!
Non-combat related chrome
-Fiber optic dermalweave: Change skin colors on the fly, all through the natural skin color spectrum, or even to wilder colors, like blues, reds, greens or oranges. Spend the extra flash for the pattern chip and be able to display all kinds of patterns with your skin tones! Stripes, spots, other animal patterns, geometric shapes and more! Try the makeup module to access dozens of colors of blush, lipstick, eyeliner or eyeshadow!
-ColorNailz: The family-friendly implant that every cool kid in Cordoba is getting! Change the colors of your nails on the fly, set flashing color patterns, or even let all the hues of the rainbow flash from nail to nail in a dizzying array of cybernetic style!
-Cybershades: Block the sun and make a statement with these hard-affixed lenses. Electro-chromatic, and with a variety of tints and finishes available, you can darken or dim them to any lighting or social situation. And of course, you can rock the ever-fashionable chrome eyecovers look.
-HardTerm305: It's 2105, LiteTerms are so 2104. With the help of a cybereye and a retinal display, as well as having wireless signal, now you too can deck anywhere, anytime. This ultra-portable deck forgoes all the hardware for a virtual system only visible to it's user's visual overlay. Stop surfing the grid and become the grid.
-The Caterwaul: This single-use chrome is affixed to the spine and works in conjunction with your SIC. In the event of death, it greatly boosts the transmission power of your SIC to alert the SIC network that you've just experienced a loss-of-life incident, along with your triangulated location. Operating on the same basic mechanics as high-end automotive security systems, this chip is able to offer clone angels a chance to try and locate your corpse in time for a cloning. Due to the consumable and energetic nature of this implant, it's highly recommended that surgeons not attempt to remove it without having prior experience in doing so.
-Smuggler's compartments. Using much stronger Myomer muscle replacements, your surgeon is able to remove enough muscle mass in your forearm or thigh to provide you with a small compartment to smuggle handheld items in. Shielded so it's virtually impossible to scan the presence of the implant, or the contents of it, you're able to fit relatively small objects into body cavities, such as data chips, skillsofts, grenades, and even smaller weapons.
-Forearm Hook: Using a small grappling hook and carbon-fiber wiring, this small mid-range hook is able to be concealed directly within your forearm, and operates on a simple spring-load and gas-shock launching system. It only takes a moment to fire off the hook at a nearby rooftop and let the ratcheting spool assist you in climbing the impossibly thin strand of wire. Optionally: spring for attaching a battox gel-cel to a forearm attachment point to automatically winch yourself up to the roof!