I'll probably be the only one to post here, much less give an actual decklist, but what the hell. Here's what my deck had grown into before I stopped playing around 3 years ago:

Pokemon
x3 Dunsparce (Sandstorm)
x1 Jirachi (Hidden Legends)
x4 Natu (Sandstorm)
x4 Xatu (Sandstorm)
x1 Oddish (Hidden Legends)
x1 Gloom (Hidden Legends)
x1 Bellossom (Hidden Legends)
x2 Lileep (Sandstorm, "Amnesia" version)
x3 Cradily (Sandstorm)

Trainers
x4 Root Fossil
x3 Potion
x2 Buffer Piece
x3 Rare Candy
x1 Ancient Technical Machine [Rock]
x1 VS Seeker
x3 Celio's Network
x3 TV Reporter
x2 Steven's Advice
x1 Mr. Briney's Compassion
x1 Rocket's Admin.

Energy
x7 Grass Energy
x3 Psychic Energy
x4 Heal Energy
x1 Scramble Energy
x1 Double Rainbow Energy

It was a constant work in progress, but you work with what you have. I refused to buy into the standard CCG mindset, throwing away money on singles and booster packs like the most serious players, and almost the entire deck was pieced together from stuff I got through trading over a long period of time. Still, it was my own invention and I'm happy to say that it was a total ***** to play against, even holding its own against Tier 1 tournament-level decks during its final days. (Unfortunately, most of the cards were phased out of organized play just when the deck started to get really good, so it never got to see any success beyond the local league.)

I won't bother giving my full strategy, but I will say this: Cradily was an overlooked superstar. Excellent card with the right support, and yet no one ever used it.

I have a rather large amount of older cards from back when they were still popular, too. Of course, I never got enough duplicates of anything other than crappy commons to really form a cohesive theme (duplicates of a card were generally considered trade bait at best), so all the decks I used against friends back then sucked hard.