Swords Dance Kecleon
In simple terms: EVERYTHING DIES TO SHADOW SNEAK OR SUCKER PUNCH... Well, not everything, but this allows Kecleon to have really powerful priority moves that all get STAB, giving it a ton of power.
Tail Glow Ampharos
This would make Amphy an amazing late game sweeper. If you're able to force something to switch, and Tail Glow on the switch, it may be over for your opponent. The only problem is that Ampharos is slow and isn't really all that tanky, which s a problem...
And just to bring it up, Mega Ampharos also really benefits from this up in UU
Earthquake Klingklang
Klingklang really needed more physical moves in general and EQ would make a great addition. Like Melons-N-Soda said, this lets Klingklang without Wild Charge it Steel-types and for a lot of damage. This also lets Klingklang hit Fire-types that could maybe live a +1 Return/Wild Charge.
Here's a set:
Klingklang @ Life Orb
Ability: Clear Body
EVs: 252 Atk / 252 Spe / 4 HP
Adamant Nature
- Gear Grind
- Earthquake
- Façade / Volt Switch
- Shift Gear
65 Defense Clefairy
If my calculations are correct, after Eviolite, this gives Clefairy base 97.5 Defense (compared to Clefable's 73) , which is amazing. With reliable recovery and Calm Mind, Clefairy can become a defensive monster
Focus Blast Kadabra
This is really good coverage against Dark and Steel-types... that's about it.... Yay...
My nomination:
All Wormadams share their moves amongst each other.
What this means is that Wormadam-Trash Cloak (the best defensively) can get reliable recovery in Synthesis
This lets Wormadam-Trash wall better with it's good defensive typing.