Ball Lightning: I have to admit, I have a soft spot for inanimate objects that are small but powerful; Mega Thunderball being a very nice example. Of course, I have no idea what this looks like (*imagines a yellow ball of light) but it sounds cute, heh. Explosive, and damaging, even though it's shared, but you can pretty much take out anything with this card. Useful.
Yeppers, it's a prettyful shiny energy ball-thingie that goes boom. :3
Gathering Storm: Geez, seven counters? That's a bit much, especially since you have to kill off seven of your own cards to satisfy its greedy needs. But, I'm assuming you're intertwining each counter for each star level of Thundercloud, so I suppose it makes some poetic sense. Yes, it allows you to bring out Thundercloud willy-nilly, but the after destruction effect seems redundant. This card is quite disadvantageous to whoever's using it, since it costs seven Thunder-Types to kick the bucket and risks dealing 1200-1400 damage before your opponent wipes it out. It's very Yu-Gi-Oh!-ish though; drawing out for the super duper summon in the last turn to annihilate the opponent with the sexy thunder sky dragon...so, super plus points for that!
Yeah, I figured seven was pretty hefty when I wrote that effect too, but - as you correctly surmised - I had a star level to account for and I couldn't think of any convenient other number to throw in. Might make it so that the counters accumulate faster, though. Although technically, you could spam up plenty of counters by tossing Thunder Dragon (Thus fetching two more by its effect), then discarding one of them and playing Pot of Avarice or The Transmigration Prophecy to shuffle the two discarded dragons back into your deck and then use Thunder Dragon's effect again. (That's already 5 counters right there :3) As for the damage...it's more of a style thing since it would be sort of weird for the whole energy buildup to just disappear when a random piece of spell/trap removal comes along. Plus, it's partly there to discourage casual removal effects.
Royal Double: Healthy support and decent stats (due to its effect). The one star level just puts me off. Seems kind of...good, for level one?
Ahh...the level is residue from the original version which copied everything (stats included) from a Curran or Pikeru. Might change that to three, although using it without the doppleganger effect is sort of pointless. x3
As for Wildfang, well ACC: there's a certain line of made-up monsters that thrives on it. And here I thought the Wildfang-Wild
kin connection was blatantly obvious. This card suits them down to a T since getting destroyed when the equipped monster leaves the field doesn't count as being destroyed by a card effect. x3 But yeah, it does carry the casual advantage of forcing your opponent to actually spend a piece of S/T removal if they want to get rid of it rather than just disposing of the equipped monster, so I figured I'd extend the favor to our furry friends in general. ^^
Now then...
Mechanicore LV line: Yeah, adding a Submarineroid-style limitation of "When it does, any Battle Damage this card inflicts to your opponent becomes the original ATK of this card. You can change this card to Defense Position at the end of the Damage Step." to the end of the direct attack would patch the otherwise temptingly easy Limiter Removal/AN Gauge exploit. :3
Trap Mechanicore: Erm...yeah, this kind of effect is what got Makyura the Destructor banlisted. Maybe if you made it so you could activate the trap cards only on your opponent's turn or something? Say..."If your opponent declares an attack while there is a face-up Machine type monster on your Field, you may select one Trap Card from your Hand and activate it (Activation Requirements must still be met)". Eh...just as a thought, although honestly: like Frostweaver I can't seem to find the breaktacular aspect of activating trap cards without a set in between. Presumably it's out there somewhere, though. =O
Mechanicore Deflector: A respectably sized beatstick that forms a field lock in multiples. Cool, although in all fairness you should probably change that to "your opponent cannot select a Machine-type monster other than "Mechanicore Deflector" as an attack target" so they have a fair shot at breaking the
very formidable lock two of these form in combination with Cyber Phoenix. :3
Revival Mechanicore: Sneaky, but unlike most Flip Summon monsters it can't flip itself face-down again, so fair enough.
Mechanicore Compressor: Cyber Dragon-proof wall with an added protective effect to it and even a decent Atk to boot. Good card all around.
Triple Power Surge: Yeah, very situational because of the hefty requirement. Also, it doesn't quite seem to fit in with the general theme of 'lock the field and direct attack your opponent silly' that these other Mechanicores have going on. Well, I guess it's a safeguard against a random Mirror Force, Torrential Tribute, or Lightning Vortex at least.
Cyber Demodulator Dragon: Heh, I see some serious hate against the card drawing spree that the competitive decks these days are so engaged in. The ability to drop this down on the field by sacrificing Cyber Proto Dragon is a nice bonus too. :3
Anyways, I'm going to revamp Gathering Storm for a wider audience:
Gathering Storm
Continuous Spell
For each Thunder type monster that is sent to your Graveyard, place a number of Ionization Counters on this card (Maximum 15) equal to half the level stars of the monster that was sent to your Graveyard (Rounded down to the nearest whole). Tribute this card with 5 or more Ionization Counters on it to Special Summon one "Thundercloud Dragon" from your Hand, Deck, or Graveyard. If this card is destroyed as the result of a card effect, inflict 200 damage to the controller of the card for each Ionization Counter on this card.
Cumulonimbus Dragon
Dragon/Effect
3 Star/Wind
800 Atk / 1900 Def
Whenever a Thunder type monster is summoned successfully, Including Flip Summon, place one Ionization counter on this card. This card accumulates effects according to the number of Ionization counters on it:
1 or more: During each of your Main Phases, you may move any number of Ionization counters from a card on your Field to another card on the Field.
2 or more: When this card is destroyed, inflict 200 damage to your opponent for each Ionization Counter on this card.
3 or more: This card can not be selected as an attack target.
Ion Cloud
Thunder/Effect
1 Star/Light
0 Atk / 0 Def
This Attack Position card can not be destroyed by Battle. When this card attacks, all Battle Damage from the battle becomes zero. Whenever this card battles with a monster controlled by your opponent, place a number of Ionization Counters on this card equal to the level stars of the monster it battles with. When this card is destroyed or removed from the Field, distribute all Ionization counters on this card amongst the cards on the Field.
Plasma Wisp
Thunder/Effect
3 Star/Light
? Atk / 0 Def
During each of your Standby Phases, select one monster on the Field and place one Ionization Counter on it. The Atk of this card becomes the number of Ionization Counters on the Field x 300.
Tempest Fairy
Thunder/Effect
4 Star/Light
1600 Atk / 0 Def
Once per turn, during your Main Phase, remove two Ionization Counters from your Field to select one card on your opponent's Field and destroy it.
Thunder Steed
Thunder/Effect
4 Star/Light
1400 Atk / 800 Def
When this card is Normal Summoned successfully, place one Ionization Counter on this card. Whenever this card battles, you may remove one Ionization Counter from this card to increase the Atk of this card by 800 until the end of the Damage Step.
Stormwing Pegasus
Thunder/Effect
5 Star/Light
2300 Atk / 1200 Def
When this card is Normal Summoned successfully, place one Ionization Counter on this card. Once per turn, remove one Ionization Counter from this card to select one Spell or Trap card on the Field and destroy it.
Chain Lightning
Normal Spell
All monsters on the Field that have Ionization Counters on them (Excluding Thunder Type monsters) are destroyed. For each monster destroyed by this card's effect, inflict 400 damage to the controller of the monster.
Ion Storm
Normal Spell
Pay 800 Life Points. Place one Ionization counter on every face-up monster on the Field.