RE: Porygon-Z (PLB) , Forgotten card?
It absolutely seems useful on paper if you were to make a Tornadus EX (PLS) deck, but that's about all its uses. No good Team Plasma pokemon can benefit from its Ability - none need Plasma Energy except for Lugia. Plasma decks run Plasma Energy solely for Colress Machine for Energy acceleration purposes. The only things that actually make use of Plasma Energy (Genesect and Lugia) either need it to be manually attached (Genesect) or just need to have one and are better off with Colress Machine (Lugia).
Besides, you can only have 4 Plasma Energy in the deck, and running a Stage 2 to move only 4 Energies is, well, pretty bad.
The reason why Aromatisse and Klingklang are/were popular is because the Energy movement made then really versatile - you can power up pretty much anything by getting Energy onto anything, and then there's also Max Potion, Cassius, AZ, etc. But this guy can move only Plasma Energy, which, again, aren't used for attacking. Again, Lugia is an exception. Think about it: stage 2, (requires at least 7 spots) which can move only Colorless Energy (and you only get 4 of them, don't forget about that) and nothing competitive (except Lugia) can make use of them, meaning it's not anywhere near Aromatisse/Klingklang in the game.