Well, Durant fits just about anywhere. You do have another Fire weakness in Gourgeist, but you have Ninetales and Tyrantrum that'd take nothing from fire moves (and Gourgeist has a 50% chance at living a Darmanitan's Flare Blitz, so yeah). Jolly, Max Attack and Speed, STABs, Rock Slide and Hone Claws (E12).
Since Aggron's gone, you have no resist for Rock types (which should be no big deal cause you have Gourgeist and likely EQ on Tyrantrum, but still) and Ice types. So a fighting type could work too (as could Durant's steel). You've got Hitmonlee, Mienshao Hawlucha and perhaps-ideally-to-not-let-a-Psychic-weakness-get-way-out-of-hand, Scrafty. Already did sets for 'em, so I'll just copy-paste:
-Hitmonlee:Unburden, Blaze Kick, High Jump Kick, Bullet/Mach Punch, Thief (TM later) for Hitmonlee. Another option would be Reversal and Endure instead of High Jump Kick and Blaze Kick or the priority, that option lets you get the Unburden boost easier, though Gems are a thing, so it's no big deal anyways.
-Mienshao: Reckless, High Jump Kick, Knock Off, Acrobatics(E12 or TM waaaaay later)/Poison Jab(E12)/Rock Slide (E12) for Mienshao (Farfetch'd for Knock Off, Acrobatics and/or Poison Jab, Camerupt>Donphan>Mienfoo for Knock Off and Rock Slide(Acrobatics is a TM you get way later)).
-Hawlucha: Unburden, High Jump Kick, Acrobatics, Swords Dance/Poison Jab(E12)/Rock Slide(E12) for Hawlucha (just continue the chain for Mienshao to get these moves onto Hawlucha) (Feather Dance is also an option to make setting up stupidly easy, which is why I'd say it's the best Fighting type in the game right now)
-Scrafty: Moxie, Dragon Dance, Ice Punch, High Jump Kick, Crunch for Scrafty. Since this one doesn't have Unburden, you can give it a Wide Lens to make High Jump Kick 99% accurate.
You've also got Poison and Steel covered, so you can use a Fairy type. Sylveon comes to mind. It's not the most stable with it's attacks, because one of the best reasons to use it is Pixilate Trump Card. 390 BP on the last hit. And all TC hits are at LEAST 80 BP, but you can run out easily (though you can also "set it up" easily, just waste some PP on wild Pokemon before a major battle).
For other Fairy types:
-Clefable's got a pretty bullshit set. Cute Charm, Minimize, Cosmic Power, Charge Beam, Stored Power...I think you see the gimmick there. Gets boring after a while, but hey, it works.
-Granbull's a good combo of bulk and power. It gets Intimidate as ability and then all elemental Fangs, Crunch, Play Rough, CC, Outrage, EQ via E12.
-Azumarill! Huge Power, Aqua Jet, Waterfall, Play Rough, Belly Drum/Bounce/Superpower/Brick Break/Body Slam.
And there's Water types. I noticed Kingdra was mentioned here, but...no. The only reason anyone uses it in competitive is either because it's the only Dragon you can somewhat use on a Rain Team OR as a Focus Energy Draco Meteor spammer (because crits ignore attack drops), but you're not using rain and we don't have DM.
Though there ARE some great water types around. They may find Ninetales' Sun annoying, but just save before a battle, see what's ahead of you and maybe don't use Ninetales or take off it's Heat Rock or something. Again, copy-paste!
Kingler, Crawdaunt, Huntail, Clawitzer, Empoleon and Relicanth are the ones that...do anything worth a team slot, while Feraligatr, Empoleon and Gorebyss are the best Water types in the game IMO. Sets:
-Sheer Force, Agility, Waterfall, Rock Slide/X-Scissor/Brick Break/Knock Off for Kingler (Archen>Corphish>Krabby for RS and KO in E12, Kricketune/Karrablast/Ninjask/Dwebble>Skorupi>Krabby for XS and KO in E12, Corphish>Archen>Anorith>Krabby for all RS and XS or all three in E12)
-Adaptability, Knock Off, Waterfall/Crabhammer, Swords Dance/Dragon Dance, Aqua Jet/Rock Slide(E12)/X-Scissor(E12)/Brick Break. Aqua Jet is pointless if you aren't using SD, chains for RS and XS are the same as for Krabby.
-Water Veil, Waterfall, Shell Smash, Ice Fang, Sucker Punch for Huntail.
-Mega Launcher, Water Pulse/Scald(E12), Ice Beam(E12)/Dark Pulse/Dragon Pulse/Aura Sphere/Sludge Wave for Clawitzer, the chain for Ice Beam and Scald is in the guide.
-Rock Head/Sturdy, Head Smash, Waterfall, Earthquake(E12), Zen Headbutt/Yawn for Relicanth (Whiscash for Zen Headbutt and EQ, Wooper or Whiscash for EQ).
-Any Ability, Surf, Ice Beam(E12), Hidden Power Grass/Electric, Shell Smash for Gorebyss. Psychic is also an option for a 3rd attack if you're too lazy to get the right Hidden Power, but HP Grass/Electric works much better. You can also go with Baton Pass.
-Torrent, Agility, Surf/Scald(E12)/Hydro Pump, Ice Beam(E12), Grass Knot for Empoleon. Chain in the guide.
-Sheer Force, Waterfall, Ice Punch, Crunch, Dragon Dance for Feraligatr.
There's also the mystery egg from the police in the Jasper Ward, which can give you, for Water types, Tentacruel, Starmie and Azumarill. For those:
-Liquid Ooze, Sludge Wave, Scald(E12)/Surf, Ice Beam(E12), Wring Out/Acid Spray. Or be real and use SD(E12), Waterfall, Poison Jab, Knock Off Tentacruel which is surprisingly fun.
-Natural Cure, Hydro Pump, Psychic, Power Gem, Icy Wind/Minimize.
-Huge Power, Belly Drum/Waterfall/Aqua Jet/Play Rough/Bounce/Superpower/Brick Break/Body Slam.