There's a few things I'll weigh in on. The big one is
Mega Sharpedo, I've had a great time using this thing on the in-game ladder. Thanks again to
Kotori for helping me theorymon about this shark on IRC. Dark STAB is always good for taking on huge threats like Aegislash and Gengar, but Strong Jaw Crunch off of Base 140 Attack smashes things. On top of that it can abuse its pre-Mega ability Speed Boost to get a scary jump on faster opponents coupled with a cool 105 Base Speed, though being forced to not Mega Evolve and Protect on that first turn against many things can be predictable and dangerous. Crunch is such a strong move that Water moves really aren't necessary, and that's reflected in its PGL stats. The option of Ice Fang is really all the coverage you need just for how good Ice coverage is for hitting stuff like Garchomp and Landorus (Ice Beam also works if Rocky Helmet Chomp and Intimidate scares you). Destiny Bond is also an awesome tool in 3v3, and Sharpedo's most common move at that, which is made even better if it can manage a speed boost. It's a really sneaky way to take out a bulky threat that can take any of Sharpedo's other moves, and it's one of the shark's best selling points. That said, even with slightly enhanced 70/70/65 bulk as a Mega it's still vulnerable to priority it doesn't resist (it survives Conkeldurr Mach Punch though!). It's still a blessing to allow it to actually take weaker hits and avoid being easily revenged by the dangerous Sucker Punch, so don't expect it to die to
everything.
Mega Sharpedo a rather competent cleaner that can ravage whole teams with just a bit of team support, and it's got plenty to keep Blaziken from outclassing it completely. However the fact that Speed Boost is only a pre-Mega ability and the greater vulnerability to priority moves are very real shortcomings so I think a
solid B rank is a good place for Mega Sharpedo. Its weaknesses are a bit restricting so B+ might be a tiny bit high, but I don't think it should be any lower than a B- rank Pokemon. I know Sash Sharpedo is a thing though I can't attest to its usefulness, though it feels a bit more niche and I don't think it's quite as dangerous as Mega Sharpedo can be.
The other thing I wanted to bring up is
Escavalier for C/C- rank even though it's not on that list. You RU players know what this thing does in RU, and from what I've experienced with it Escavalier basically does the same here (Assault Vest, Choice Band...
Assault Vest). Escavalier performs nicely on offense teams that really need a solid answer to Trick Room (might even function effectively on a Trick Room team itself), and I've found it to be neat on Blaziken teams in particular for that reason. Its strong STAB combo allows it to function as a cool Psychic/Fairy check with Assault Vest, and access to both Pursuit and Knock Off can really let it punish the likes of Cresselia and Porygon2 with proper VoltTurn support. Drill Run also lets you punish Fire types like Blaziken and Heatran that think they can switch in safely too. In addition to that, Overcoat gives Escavalier the ability to beat Breloom 1v1 thanks to a Spore immunity and x4 Grass resist, which is super neat. That said, Escavalier is huge setup bait for various physical threats and basically lets things like Salamence and Charizard come in for free, so it absolutely needs team support against other offensive teams. Escavalier is a nifty option for teams that struggle with slower defensive teams or Trick Room, though being setup bait for some horrifying sweepers limits its usefulness against faster offensive teams (that's not to say it's useless against them though). Regardless I think there's a place for Escavalier somewhere, and I think C/C- is that place. It could be argued for D rank instead though I think Escavalier has
just enough of a niche to push it into C or C- rank.
I dragged on a lot more than I expected, but the tl;dr of it is
Mega Sharpedo for B rank and
Escavalier for C/C- rank. Experimenting with cool new stuff has honestly been my favorite thing about this metagame so I definitely plan to try some new things in the future.