What gmc truck has interchangeable parts with my 2002 gmc sierra 1500?

These were built on the GMT800 platform, and they're all nearly the same - but it depends on the components. Engines are usually interchangeable as long as the codes are the same, as well as transmissions to a point - the early ones (1998/99) use the 4L60E and the later ones (1999-2006/2007*) use the 4L60E (4.8 Vortec), 4L80E (HD/5.3L) and the Allison 1000 for the diesels (DuraMax, DO NOT FIT IN GAS TRUCKS; too big). Even a lot of the external body panels change being a body on frame truck.
*I am putting an asterisk here is 2006 was the GA end of the GMT800 to the GMT900, but 2007 Classics were available as rentals until 2008.

The grille is murky - as long as you can put the GMC badge on a bowtied grille and move the clips, you are good. Tail lights are generally also the same until you get into the Caddys.

Where things get messy is the interior - the GMC models tend to be upscale or use things like different radios where you need to make sure the radio you're installing works in the Sierra 1500, and you need to code it with a Tech II or an emulated Tech II, or defeat the immobilizer as these use the radio for that -- GMT900 did away with that, but they aren't as good as the GMT800 being post GFC/New GM. One of the most notorious "no swaps" is the cluster - 2004+ uses a different protocol. Radios are less of an issue in this era as GM did these as cookie cutter trucks, but the GMT900 is when they move to the GMCs being luxury trucks over time.

The throttle body is also messy - 2004+ use electronic, the older ones are mechanical. Frames also do not carry due to the wheelbase and leaf spring vs coil spring setup. This is a fab job. HEADS UP ON THE TRANS: Yes, the 4L60E is the same but 2004+ uses a different harness then the old ones, you have to harness swap them to swap the solenoids.

As to the immobilizer bypass you have to tear it down as I won't link anything but you solder a resistor between yellow and black - it has to be 2.7k-4.7k, use a variable resistor until you can start it every time. YOU ABSOLUTELY NEED THE TECH II OR A ALL SYSTEM BI SCANNER WHICH CAN TALK TO PASSKEY II TO USE SWAPPED OEM RADIOS!

@alejandro7810 you usually do a parts interchange by knowing which part you want to replace. Otherwise you are looking for a large database of parts and interchangeability. There are some free ones like the one on here but again, they ask for the part.

The only other "list" I know, is the Hollander Interchange Manual but it's quite costly