Q: Got a power mac g5 from a friend, what parts am i missing?

Can't be certain because of the picture resolution, but it would appear everything but the boards are needed. And, that assumes the power supply is behind the piece that says G5. But that is not a solid assumption.

Now, were you to install everything that is missing you would then have a decade old and obsolete, unsupported machine that cannot run any Intel software as required nowadays.

No, sorry. You might try iFixIt for something like that. Or you can just sell the case. Not sure of the going price, but there are Hackintosh builders who like to buy old cases for building a new computer with different parts. Don't ask for more since there is no support here for that sort of thing.

Vintage and obsolete products

Apple has discontinued support for certain technologically obsolete and vintage products.

Vintage products are those that were discontinued more than five and less than seven years ago. Apple has discontinued hardware service for vintage products with the following exception:

• Products purchased in the state of California, United States, as required by statute. Owners of these products may obtain service and parts from Apple Service Providers within the state of California, United States.

Obsolete products are those that were discontinued more than seven years ago. Apple has discontinued all hardware service for obsolete products with no exceptions. Service providers cannot order parts for obsolete products.

All retail Apple Stores and the Canadian, European, Latin American and Asia-Pacific operating regions follow the U.S. product list, but make no distinction between vintage and obsolete. When applied to the retail Apple Stores and these operating regions, all products on the U.S. Vintage list are considered obsolete.

https://support.apple.com/en-gb/HT201624