What gen3 non-legendary Pokemon you have powered up and used in raiding, attacking or defending gyms.
Now that gen4 will be released soon. I took a look at the non-legendary Pokemon I have powered up and used from gen3 and the list is very short:
Gardevoir (defending gyms), milotic (defending gyms) walrein (for Rayquaza), salamence.
I'm level 40 and have 6 million stardust so it's not like I don't have the resources to spend. I raid daily with a small group but I only power up what I need. I hope the release of gen4 will make more Pokemon relevant.