Since there is no specification of this being a question for Singles or Doubles, I will take the opportunity to provide some examples in the Singles Metagame:
- Bulky Garchomp + Specially Defensive Skarmory [sets can be found on Smogon]
This is great for racking up hazards. Garchomp punishes physical attackers that make contact with Rough Skin + Rocky Helmet, provides Stealth Rock, and can phaze out mons with Dragon Tail, while Skarmory lays down Spikes, phazes out mons with Whirlwind, shuts down walls with Taunt, and tanks attacks from Mega Diancie and Mega Gardevoir.
PAIRS WELL WITH MEGA SABLEYE (magic bounce is appreciated versus other hazard teams) OR BISHARP (who can make an opponent hesitate to use Defog)
This pair, while not as synergetically capable as others, does well with dealing with a majority of attacks in general. Mega Scizor is a great answer to top tier threats such as Mega Altaria, Mega Metagross, Gengar, Clefable, Mega Diancie, Mega Gardevoir, Bisharp, and much more. It can provide a slow and bulky U-Turn, priority in Technician boosted Bullet Punch, has access to Roost, Defog, or Knock Off as support moves, while it can even clean up late game with setting up Swords Dance. Clefable is a great support mon AND sweeper, spreading some yellow magic (Thunder Wave), facilitating a sweep for Mega Scizor and teammates alike. It can heal itself up nicely with Softboiled, and can become a deadly sweeper with a Calm Mind or two under its belt. Its Ability Magic Guard can be used to make ot a great blanket check for many mons, as it ignores residual damage such as stealth rock, sandstorm, leech seed, toxic and burns, etc.
PAIR WITH A BULKY WATER SUCH AS KELDEO, MANAPHY, SUICUNE (to handle Fire types, which give this core trouble) OR TYRANITAR (to effectively deal with Talonflame and Charizard Y)
- Hippowdon + Clefable + Ferrothorn
This trio is specialized at taking almost any kind of hit. The trick to this core is that it usually works best when they're all Mixed Walls. Hippowdon can handle mons such as Talonflame and Electric types, and of course much more. Clefable can handle Lati twins when you can see (by guessing) their team being a Hidden Power Fire Variant (a good skill to have) and can be the prime switch in for most attacks thanks to it not being worn down by hazards or status. Ferrothorn is more for fairies, who usually cannot KO Ferrothorn with a STAB attack + Coverage Attack (Such as Mega Gardevoir and Mega Altaria). As you can see, this core struggles with strong Wallbreakers such as Charizard Y and Life Orb Tornadus-Therian, so build around this core to work out and eliminate weaknesses.
PAIRS WELL WITH MEGA LATIAS, MEGA SABLEYE, BULKY STARMIE, OR SPECIALLY DEFENSIVE TALONFLAME
Note: will add more upon request
Edit: To answer your question, it honestly depends on what type of team archetype you wish to use to define what would work best for you. Balance and Stall will often carry walls, while Bulky Offense will usually carry tanks. Hyper Offense will almost always only carry sweepers.
