Any Pokemon worthy of 100k stardust?

dragonite, lapras, snorlax, vaporeon, and Gyarados not in that order.

Any Tier 3 or better attacker with IV 91+ and perfect attacking moveset.

In addition to the other. High IV personal favorites and 100 IV pokemon

I have powered up many Pokémon from level 20 to level 30+ so I do think so. But then again I'm pretty obsessed with IV's and movesets so I don't know what's actually reasonable. I spent 70k more stardust on 5% more IV's.

dragonite, snorlax, lapras and exeggutor. Maybe Golem, Gengar and Alakazam because they are my favorite pokemon in gen 1

Absolutely! Not just a few, but basically any/all that fit my criteria. Though if I have two mons with a preferred attacking moveset, I only power up the one with the better IVs and leave the other for training/trading.

Fully Power Up (Currently to Level 37.5)
1. Listed as top tier attacker per GamePress and has an IV of 90%+.

Power Up To Level 30
1. Listed as top tier defender per GamePress and has an IV of 90%+. Previously I was working a few of these up to max but with the gym changes I stopped at 4 of those.
2. Has 100% IVs. Doesn't matter the mon or moveset (though I only power up one if I get a duplicate moveset mon).

100k Stardust actually isn't all that much when you get to the higher levels. You'll probably get that much while levelling from 30 to 31 :P (can't be bothered to look it up right now, I'm only level 28 though).

Most good pokemon will be worth 100K dust getting to level 30. The real question is which pokemon are worth training beyond 30. Probably limited to Legendaries and the extremely elite (Dragonite/Snorlax and a few others).

Not stated, but maybe Venusaur to deal with the masses of Vaporeons out there...Vine whip is a lot faster than Zen Headbutt...

If I think it's a good defender I don't mind spending more than just 100k.

And then Niantic made Gym defense useless.

The most I spent on a single pokemon was probably 80k on my Slowbro with Confusion+Psychic, because he's my favorite Gen 1 pokemon, and on my Lapras because it's Lapras. I took both from level 20 to 30.5.

The other mons I maxed out - Vaporeon, Flareon, Jolteon, Exeggutor, Poliwrath and Vileplume - already started from higher levels.

Save all that dust for the gen 2 update in December

Also depends on how rare a pokemon is in your area. Many places have an abundance of Eevees, you could come across a high CP AND high IV one to evolve. Same with Exeggute and Magikarp (near water). That alone might save you 50k stardust or more.

Lapras and Snorlax though are very rare, so when you get one with good IV and moveset, it's probably worth powering up!

Pokemons you will love.

100%IV pokemons to show off in the gyms :D

Lickitung !!!!!