I got this idea from video games actually, specifically the PS4 game Horizon. The idea here is that once a large enemy is damaged enough the Cypher Thief can yank bits of the robot apart and use it during the battle against the robot. The idea of Cyphers I “stole” from Numenera.
Edit (14042019): I ended up dropping cybertheurgy and using Arcana instead in my last campaign. I feel this works better (see comment).
You have a keen eye and a fast hand. You can disassemble robots so quickly you can turn their own body against them and gain the following benefits:
- With disadvantage, you may attack to disassemble a robot so long as it is one size category larger than you and bloodied. You make an Arcana check against the robot you are attacking and attempt to wrest a component from the body of the creature to use against it. On a success, you may roll on the cypher table, and if appropriate, immediately use the acquired cypher against the robot you made the disassembling attack against. On a natural 20, you may roll on the artefact table or gain a trophy weapon instead of the cypher table.
- You may now carry three cyphers at a time without causing an “incident”.
Cyphers, or relics to the common folk, are one-use, cobbled together bits of technology that characters frequently discover and use. When the PCs come upon an old device, defeat some artificially enhanced or designed creature, or simply sift through the ruins of the past, they can scavenge a handful of new cyphers.
Because the technology of the past is unknowable, cyphers are often determined randomly. A DM, however, can place them intentionally as well. They’re one-use cool powers that can heal, make attacks, or produce effects like nullify gravity or make something invisible. The sky’s the limit. But they’re always consumed when used. And they cannot be hoarded. Collecting cyphers together in one place, or carrying many on your person can potentially have a detrimental effect–from the long term (illness) to the short (explosion!). So essentially, characters only carry a few at a time. However, they are found with such regularity that players can be pretty free with their use. There will always be more. And they’ll have different benefits.
This means that in gameplay, they’re less like magic items and more like character abilities that the players don’t choose. Which leads to really fun game situations where a player gets to say, “well, I’ve got an X that might help in this situation,” and X is always different. X might be a bomb, a short range teleporter, or a force field. It might be a powerful magnet or an injection that will cure disease. It could be anything. Cyphers keep the game fresh and interesting. Over time, characters can develop the know-how to be able to safely carry more and more of these, so they really do end up seeming more like character abilities and less like gear.
A character may only carry two cyphers at a time.
Trophy weapons are powerful artefacts directly taken from a machine enemy. For example a myrmidon’s laser whip. You may use this item as normal per the creatures statblock but it depletes on 1 or 2 and each time you use it this number increases by 1 until it still working entirely.
Artefacts are the tech devices that you probably expect in the game. These are devices of a more permanent nature (unless they run out of power) with more straightforward applications. Weapons, armour, utility items, and so on. Still, rarely are they straightforward. It’s far less likely to find a “gun” than it might be to find some item that can be used effectively as a ranged weapon but might have originally been some kind of power conduit that has been modified and adapted as best as Ninth World understanding could manage. Some characters, given the right tools and parts, will be able to construct these on their own. Any permanent magic item from the DMG is an artefact though the common folk still call them magic items.