

Mega Magmortar
Art by DeathGaronRyo
Stat distribution:
HP: 75
Attack: 105 (+10)
Defence: 112(+45)
Sp. Atk: 155(+30)
Sp. Def: 130(+35)
Speed: 63(-20)
Type: Fire
Fusion Cannon: This ability transforms spread damage special moves into single target moves and boosts their damage by inverse spread multiplier.
Moveset addition:
Sludge Wave
This will give it a different niche from other Fire type Megas, being a bulky single target burst damage dealer. It will mainly use Heat Wave(/Lava Plume for better accuracy and burn chance), Sludge Wave and Thunderbolt(although not boosted). Magmortar like Electivire does not have a deep move pool.
With damage multipliers like Sun and helping hand it can threaten even resisted KOs.
If you are interested you can check out the Mega Electivire concept I posted last week: https://www.reddit.com/r/stunfisk/s/4I1M2qk5Bu
Mega Dragapult
Art by PokieKC
The last upload was taken down due to the image used(my bad, should have read the policies carefully).
So reuploading this Mega Dragapult Concept
Mega Electivire
Art by Chevi Master
HP: 75
Attack: 143(+20)
Defence: 107(+40)
Sp. Atk: 115(+20)
Sp. Def: 85
Speed: 115(+20)
Type: Electric
Stats are distributed in typical GameFreak fashion, like in the lower attacking stat. Speed is +20 giving nod to its agile Electabuzz roots.
Mega Electivire turns into a big brute due to overwhelming power of mega evolution.
Before anyone says Brute Force is a broken ability, it's worse than Sheer force + life orb and here it is on a mega, which cannot hold any item. Keeping in mind the moves Electivire can learn in SV, the most powerful are Hammer Arm, Wild Charge, Darkest Lariat, then comes the elemental punches and Brick Break. Supercell Slam and Cross Chop are unreliable and Earthquake won't be boosted.
So considering all of this Mega Electivire still won't be a top tier mega, especially in a format with Mega Metagross, Mega Salamence, etc
Edit: To clarity, secondary effects here are beneficial effects like inflicting status or stat drop on target and stat increase on user. Like in Sheer Force. But unlike Sheer Force, a move does not need to have additional effects for Brute Force to apply.
New Ability for Mega Skarmory
Mega Skarmory really suffers from Mega Zard Y being so prevalent. It's ability Stalwart does not help it at all. And with only 140 base attack it isn't hitting hard as a mega should either.
Solid Gold (yes some inspiration was taken from Good as Gold) grants immunity to any super effective damaging moves when at full HP. Which means Fire & Electric type attacking moves won't have any effect. Status moves like Thunder Wave and Will-O-Wisp will still work.
This will allow M-Skar to set up a Swords Dance without the fear of being one shot-ed. And click Rock Slide/Dual Wingbeat/Iron Head into opposing mons.
Yes, it could be given Tough Claws as it gains gigantic claws but many megas now have Tough Claws, and what will be unique about it!
Also it isn't a broken ability on M-Skar considering its HP stat is only 65. This ability won't make it super relevant but will make it
Ability Change for Mega Scolipede
Shell Armor just doesn't cut it. Mega Scolipede already has a steed stance, so Stamina fits right in. With 145 base attack it isn't an offensive powerhouse as a Mega, nor due to its 60 HP it can be a great defensive wall. So it will require all the boots it can get.