Alright, full tweaks. I'll be using the actual sets their from rather than the theme decks for my additions:
2 Garchomp from Mach Strike
2 Garchomp from Towering Heights
2 Gabite from Mach Strike
2 Gabite from Towering Heights
3 Gible from Mach Strike
1 Gible from Towering Heights
2 Passimian from Towering Heights
1 Lucario, from Mach Strike
2 Riolu, from Mach Strike
2 Spiritomb, from Mach Strike
2 Gumshoos, from Mach Strike
2 Yungoos, from Mach Strike
1 Mew, from Towering Heights
20 Fighting type energies
4 Cynthia
2 Professor Kukui
2 Nest Balls
2 Green's Exploration
2 Switch
1 Rescue Stretcher
1 Martial Arts Dojo
1 Pal Pad
1 Escape Board
-33
-2 Professor Kukui
-2 of Gabite in any combination, whether that be removing one of each or both of one
-2 Gumshoos
-2 Yungoos
-2 Spiritomb
-2 Passimian
-2 Riolu
-2 Nest Ball (good, but not Standard legal at the moment; only legal in Expanded and most places only run Standard tournaments)
-2 Switch
-1 Rescue Stretcher (again, good, but not Standard legal anymore)
-11 Fighting Energy (you want to be drawing into trainers and Pokemon more than you do energy for the most part because there are ways to get the energy out anyway)
-2 Green's Exploration
-2 of the Ultra Prism Garchomp (Mach Strike one)
+30
+2 of the Forbidden Light Garchomp (it's fighting type instead of Dragon, so it can take advantage of an addition further down my list)
+4 Triple Acceleration Energy (for setting up the Royal Blades attack faster)
+3 Pal Pad
+4 Riolu UNM (only has 60 HP so you can actually grab it with Professor Elm's Lecture which is a huge help)
+3 Lucario UPR (since you run Garchomp, might as well go all in and run enough copies to take advantage of its ability more consistently)
+2 Great Catcher
+4 Professor Elm's Lecture (Good for fetching a lot of Pokemon fast, but only those under 60 HP)
+3 Pokemon Communication (Good for swapping some of the Pokemon you got with Elm's for Pokemon that you can't get with Elm's like your Garchomp and Lucario)
+1 Diancie Prism Star (its ability boost fighting type attack damage by 20)
+1 Power Plant (shutting down the abilities of GXs)
+1 Martial Arts Dojo (since you'll fall behind)
+2 Lillie (Draw Power)
+3 Rare Candy (bypass Gabite into a garchomp, you'll need this speed at leagues)
+1 Viridian City Gym (for getting basic fighting energy from the deck)
Dedenne GX is a very nice setup card to have if you can obtain it and you can get away with 1 in this deck, and I'd personally swap it out for one of: Triple Acceleration Energy, Viridian City Gym, or Power Plant.
Though I do totally expect this list to get bodied at a league due to the fact that neither Garchomp deals with the big Tag Teams that dominate Standard currently very well at all, but at least this list should give you a better fighting chance.
Maybe drop a Pal Pad for a Brock's Grit if you're finding yourself burning through Pokemon and Basic Energy very quickly.
Jesus Christ that is a lot of cards. I'll try to get my hands on this stuff. I don't plan on going very far, and I would spend more, but then my parents would kill me. They're already mad at me for only getting Pokemon cards for Christmas.
Cards I possess out of the recommended:
1 Triple Acceleration Energy
3 Pokemon Communication
1 Power Plant
1 Lillie
Yeah I have a long way to go. I'll probably get a couple of these in the 3 theme decks I bought. Maybe a Lillie or 2 pal pads will be what I pull at most. I can buy a bunch of this over the next year though.
Offers I've found for these cards:
Triple Acceleration Energy: 47 cents per card. Condition new
Forbidden Light Garchomp: All below 2 dollars. Condition new
Pal Pad: All below 2 dollars. Condition new
Riolu UNM: All below a dollar. Condition new
Lucario UPR: All below 2 dollars, Condition new
Great Catcher: All below 3 dollars, Condition new
Professor Elm's Lecture All below a dollar, Condition new
Diance Prism Star: All below 5 dollars, Condition new
Lillie: All below a dollar, Condition new
Rare Candy: I think I have 1 or 2 of these, I'll check back about these ones. All below 3 dollars, Condition new
Viridian City Gym: I can't find any of the new cards, only the old one. Where would I get one?
Dedenne GX: 30 Dollars roughly
Martial Arts Dojo: Why can't I find any single card deals? I found sets of 4 for below 2 dollars
Total Estimated Cost: 75.41 dollars, if the deals are at the middle part of costs. Not including Viridian Gym, because it doesn't exist to the online shopping world.