Magic item creation rules are a pain. Except for Shadowrun. Although most runners will probably just buy their magic items. Why do they work in SR? Because they are just another kind of equipment. And making them yourself is basically just negotiating a discount using the Enchantment skill instead of whatever social skill would be relevant otherwise. They also do just three things:
- Add bonuses to magic rolls
- Add bonus to melee weapon attack rolls (only relevant for ki-Adepts, who can’t use cyberware)
- Keep up one of your spells without concentration
In short they are just specialized equipment for certain kinds of characters. Magic items in games like D&D are different. They are meant to be interesting loot. You can have one or the other, but not both at the same time. So great loot should be like:
- It’s unexpected. Whereas skill and powers are something players actively choose, this is usually not the case the with loot.
- It’s tied to the shared fiction. The thing came from somewhere, even if it’s only “found in that dragon hoard back then”.
- Looted magic items can have character. Not necessarily in that they are intelligent, although that is common too, but a certain idiosyncratic behavior.
- They can be gamechangers under the right conditions.
As a GM you can put loot in your adventure and have it do whatever. There is little reason to limit them or make them balanced in terms of the rules, as long as the GM is handing them out one by one.
If you want to be extra careful, make sure loot never flat out increases your game’s attributes or whatever you call the most basic stats. Bonuses tend to be comparably boring in general, and bonuses to base stats even more so. Instead you can have it do interesting things in absolute terms. It let’s you can fly. It lets you see in the dark. Ever comfortable shoes. A bag which is bigger on the inside. A sword that stops the beating heart of any creature it cuts. Effects can be big, as long as they are clearly delineated. That sword does not do anything against plant monsters, undead and robots for example.
If you need some additional limits for individual items, here are some ideas:
- It can only be used x times.
- It can only be used once a day / week / month / year / decade.
- It’s unwieldy. You need a bag / suit case / carriage to move it.
- It consumes some kind of fuel, which is expensive / rare / grisly.
- It has some side effects on the environment.
- Is has some side effects on the user.
- It requires certain skills or knowledge to use correctly.
- It only works on certain targets / under certain conditions.
- It is overkill for most use cases.
- Using the thing is blatant in terms of sound, light or more metaphysical qualities.
You can also combine different effects and add different limits. Like a base effect the is free, and some extra sweet stuff is limited. Here is an example from my last campaign:
These straw puppets are about 50cm in height and can expertly steer any cart or coach, when given the reins. They can find their way to any place they’ve been before. They were invented by the among the mainly goblin tribes of the Dry Lands, and appear to have some ritual value. As such they are usally not for sale. In one instance a puppet was overheard speaking with a creepy whispered voice, in what likely was some goblin dialect.