Alright well then based on this information livers should also be possible to cast magic with since they're organs.
If you want information on other things that could be used to cast Lyrical Nanoha magic then you'll need to specify other things about how Nanoha magic is cast and how Linker Cores and Devices work.
Okay then, how about this to help explain things.
A linker core is a organ that helps channel, store, and manifest magical energy for various effects. It is possible to engrave, remove, and transplant them. With a transplant being used to create a Familiar that is connected to the mage. Now magic can be used in multiple different styles but in the Nanoha Universe, they are usually used with a Device.
Also, most Mage's ranks in the Nanoha Verse rate the quality of the Linker Core to determine what Rank you are.
A Device, which can come in multiple forms, are tools used to allow for easier casting of magic. A wand from the Potterverse would be considered a archeic device to the TSAB for example.
Most Devices use connections that are from synchronization with said device, higher sync rate means a better usage, to have a built in computer to cast spells. Most people use what are called 'Storage Devices' which are more common and have low intelligence but high speed processing. Then there are weapon based ones with a special magazine system called "Armed Devices' that are meant for combat. They are a middle ground when it comes to processing processing speed and intelligence.
Next, there are Inteligence Devices. These are Devices that have full on AI support and can make requests or even act to defend their wielders when said mages are unable to do so. And finally, there are also Unison Devices. The most powerful form of Device it can be argued. These are fully sentient, self aware, and fully sapient like a living person. Beyond being able to cast magic themselves, they can fuse with their partner and augment their wielders mana control and other forms of assistance. They take the appearance of living people that can change sizes, fly, and are practically living people.
And before anyone asks about the 'magazine' system that Armed Devices have, and can be found in some Intelligent Devices, here is what THAT does. Each magazine holds multiple rounds, yes they can look like bullets, that hold excess magical energy that can be added to the casters spell at will. But at the risk of damaging their Linker Core as seen by Nanoha Takamichi multiple times.