Onyx Tanuki
Ma! There's a weird 'nuki in the yahd!
Carbink/mixed support/tank
nature/bold
item/light clay
EV/max hp and defence rest goes into sp attack
ability/clear body
moves/moonblast/calm mind/reflect/rest moonblast works wonders with calm mind the boosts let you ko many pokemon and tank many others even some not very effective hits can be damaging if you have managed to score multiple boosts just don't get greedy reflect is yur best bet for boosting your defence and tanking from the other side while supporting your team if you need to switch out most the pokemon you'll be running from will be physical which lets you help your switch ins survive rest lets you heal but more importantly the horrible sleep effect gets rid of status so if you've managed to take out your main counters and are hit by a toxic you can just laugh and heal it up before it gets too damaging continuing to tank over the two turns your asleep
this set is alot better then it looks started as a just for fun messing around set till I found it was vible vs many ou pokemon it dose have weaknesses but with good use of teamview and smart playing its easily a great set to use for someone who has stealth rock and sp defence covered the set lets you set up very easily and unless you are taunted before you can get a calm mind up taunt dosen't bother this set as much as you think I simpley get into something I know I can take a hit from and am sure it dosen't have taunt then calm mind or reflect depending on the other team which is needed most even if they switch to a taunter it is too late if you've got 1 or 2 calm minds you will likely blow them away with moonblast steels are the only pokemon your likely gonna run from after a boost but with good switch ins who love the reflect support from carbink its a force to take into account I can post some battles or you could try this yourself just play smart and use rest wisely since setup sweepers will be lured to a sleeping carbink
I personally would give up Rest and give it either Power Gem, Light Screen, Safeguard, or Stealth Rock. I don't know a lot about how it'd work for a doubles match but in singles, any tank that doesn't really have reliable recovery either is going to need Leftovers or to be supported by a pokemon with Wish, and I'd stick to the latter for this one. If you can include a defensive Bug type in your team to handle Ground and Grass attacks and a Water to take Water and Steel attacks, you'd have a pretty decent defensive core (though it really depends on what tier you're in; Carbink is NU, so it could fit in any team legally). Dragon/Flying is another option, resisting all of Carbink's wealmesses and being neutral to Steel, but if you're in NU or RU you're pretty much stuck with Altaria for that, as the majority of the good Dragon/Flying types that can take a hit are in UU and OU. Its defenses are good enough that you could feasibly ignore investing in them, but investing in SpAtt is really only going to take you so far with 50 base, so your choice to invest in Def is probably the wisest. If you're going for a defensive boost, I'd probably use Light Screen before Calm Mind, just in case the opponent phases Carbink out. Safeguard would be a great option if you have a team that would be crippled by status, and Stealth Rock is a great idea to set up in any tier if possible.
If you're going for an OU team, not only would I say Power Gem is a good idea, but I might even suggest taking it over Moonblast. It's gonna be your primary means of handling Talonflame and any form of Charizard; after a CM or two you'll be able to OHKO them, and while M-Char-Y can hit you hard with Solarbeam if you don't set up a Calm Mind or Light Screen beforehand, M-Char-X and Talonflame will struggle to do all that much damage at all. You might think about Conkeldurr, but generally they can survive several hits of Moonblast, and are better handled by something that'll Knock Off their Assault Vest before you even try and take them down; a Granbull or a Wallbreaker Togekiss would be much better at taking Conkeldurr on, with the former having considerable resistance to its moves and 2HKOing with Play Rough even without a boost, and the latter able to 2HKO with Air Slash even through an Assault Vest and having a better than half chance of Flinching it to prevent it from hitting back with Ice Punch. If you include either to handle Conkeldurr though, you may want to be very careful to include something that can take on strong Steel types like Aegislash and Lucario. You might do better with Moonblast down in RU and maybe UU, though, since the only Fire/Flying threats you'll be seeing there are Moltres and maybe Fletchinder.