Mega Ninetales
Type: Fire/Psychic
Ability: Solar Power
HP: 73
Attack: 76
Defense: 75
Sp. Attack: 131 (+50)
Sp. Defense: 121 (+20)
Speed: 130 (+30)

Would be decent if you get the sun with Drought before megaevolving and then just abuse that 131+50% Sp. Attack before dying from the sun or something else

>>26970485
Mega Tentacruel
Water/Poison
HP 80
Atk 70
Def 65 --> 101 (+36)
SpA 80 --> 113 (+33)
SpD 120 --> 151 (+31)
Spe 100
Ability: Regenerator

Mega Ambipom
Type : Normal/Fighting
Ability : Skill link
HP : 75
Attack : 140(+40)
Defense : 86 (+20)
Spe. Attack : 60
Spe. Defense : 86(+20)
Speed : 135 (+20)
Has acess to tail slap bullet seed rock blast and arm thrust (25 bp)

>>26970226
Mega Hydreigon
Type: Dragon/Dark
Ability: Contrary
HP: 92
A: 105 ==> 140 [+35]
D: 90 ==> 110 [+20]
Sa: 125 ==> 150 [+25]
Sd: 90 ==> 110 [+20]
Sp: 98 ==> 98 [+0]
(Mixed Attacker)
Becomes a grounded Hydra.

>>26971551
Mega Crobat
Type: Poison/Flying
Ability: Prankster
HP: 85
A: 90 ==> 120 [+20]
D: 80 ==> 110 [+30]
Sa: 70 ==> 80 [+10]
Sd: 80 ==> 110 [+30]
Sp: 130 ==> 150 [+20]
(Physical Attacker/Support)
Ninjabat.

Mega Ledian
Bug/Fighting
Ability: Huge Power

55 -> 55
35 -> 65(+30)
50 -> 100(+50)
55 -> 55
110 -> 100(-10)
85 -> 115(+30)

>>26971656
Mega Dragonite
Type: Dragon/Water
Ability: Multiscale
HP: 91
A: 134 ==> 154 [+20]
D: 95 ==>115 [+20]
Sa: 100 ==>110 [+10]
Sd: 100 ==>120 [+20]
Sp: 80 ==> 110 [+30]
(Physical sweeper [bulky/fast])
Sea wyvern aka what Dragonair really should've become.