What to do with these critters

Never powered up anything? What's your dust count?

I'd probably max the Gyarados, AT Vape, and Rhydon.

I'd power up gyarados. People would argue that he is not that great or he's overrated but at the end of the day, he's still better than 70% of the mons out there. plus you have a really good attacking move set.

Vap WG/AT for def if you don't have a lot already.

First and last aren't worth powering up, the ones in the middle are. How to prioritize them depends a bit on what your needs are.

Gyarados and vaporeon for sure, perhaps even Rhydon with that move set.

if you need a good grass type attacker victreebell will do just fine. If you can dodge she sill serve you well.

You have a nice collection of dust there.

I would spend dust without hesitation on mons like Blissey, Snorlax, Dragonite, T-rex where they have decent IVs.

For species that are not too rare like the mons in your list, I would generally refrain from spending dust on them because all you need is a high CP specimen to slot into gyms.

So if you haven't got Blisseys, Snorlaxes, Dragonites or T-rexes to power up, I would go for the Gyra or the 1st Vape on your list, maybe the Rhydon... these would be for pure CP plays.

Power up Gyarados and Rhydon for gym placement. Vap and Egghead for attacking. I usually power up my attackers up to lvl30 only, so that i can use my stardust on pokemon with high CPs.