I am here to add to the avalanche.
Alright let see what i can think off. Hope i am not to late :p. Tauros crest: Return the to gen 1 crits tied to speed. The faster tauros is the more likely that he will crit.
Brings back our good old bull and makes him usefull.... sometimes. Miltank crest: Lactose intolerant. everyone dies of diarrhea. That's all.
In all seriousness maybe that's not such a bad idea. All healing you get or food you consume when she's out will give you an ailment for a few turns ( overtime damage or poison damage). Makes milkyway extra annoying. Nidoqueen crest: Immune to status moves (can still get status by other moves like flamethrower) + get's life steal on all it's contact moves (20%/ 15% of it's missing health or somthing). Nidoking crest: Speed boost when hit by a super effective move + life steal (as describe above).
Both King and Queen get a bit more sustain, Nidoqueen can tank more and king can retaliate better given that he isn't that fast. Luxray crest: Give it the dark type + predatory senses ( If opponent health goes red luxray get's speed and attack boost, Can only happen once per switch in.)
Predators will double their efforts to take down prey when its hurt. Gives luxray some much needed speed. Delphox crest: Magic bouncy guard, i dunno. All none direct damage will be returned to the opponent (like sand storm damage and stealth rocks).
For a pokemon that's supposed to be a mage it can apparently only pickpocket with magician wich is kinda lame compared to greninja's protean ability. Samurott crest: Changes it's god awfull 3 stage evolutions design. Nobody needs a fat slow samurai on four legs, how the hell does he even draw dem swords? Decidueye crest: Swap speed with sp.atk. + Phantom touch (all contact move have a chance to make you flinch).
70 base speed? Why? This robinhood ninja guy is slower then blastoise a chonky turtle, and learns no special moves. Sometimes i don't get you game freak. Aurorus crest: During hail it get's increased (40%) defense and sp.def. Becomes immune (or reduces damage off) to steel type moves.
Aurorus Borealis -> Appeares because off magnetisme and radioactivity. Aurorus get's a magnetic field that redirects and protects it from da evil steel. Tyrantrum crest: 1.2x speed + ambush predator (damages all pokemon that switch into it, reversed pursuit )
Research shows that the Tyrannosaurus rex probably was a ambush predator and relied on it's camouflage making it hard to see. Goodra crest: Gives it the fairy type + adds passive healing or that all poison and water type move heal goodra. Or blubber armor reduces all incoming damage by 15%.
I like goodra (figures, username checks out. Not french wouldn't eat it though.) but it's really bad compared to the other pseudo's. Goodra lacks defense and recovery to stay in the fight and mono dragon isn't that good. Can't think of anything amazing for goodra just yet. Vespiquen crest: reducees speed by 25% but big butt. Hive guard, the hive will protect her from one attack and give all order moves +1 priority.
PROTECT DA QUEEN. Bisharp crest: Terminator Bisharp will ingnore all stat buffs and defenses like protect/ light screen. Boost it's speed by 1.2x
Looks like a power ranger version of the terminator. Let it act like a merciless killer. Omastar crest: PRAISE THE HELIX, the opponents team will join your team.
That's all i can think off for now.
