Smogon kind of let me down again, so I had to do a bit of my own research for this question. Anyways, here's the standard Tyranitar set, which is more than enough to OHKO both Ho-Oh and Calyrex.
Tyranitar @ Sitrus berry/Chople berry
Ability: sand stream
Tera type: rock
EVs: 252 HP / 252 SpD / 4 Spe
Careful nature
- knock off
- stone edge
- earthquake
- stealth rock
With the Sitrus berry, it should survive 2 hits from non-choice band Ho-Oh's earthquake. If you want to check Tera fairy Ho-Oh or Calyrex, you can replace earthquake with heavy slam. If your opponent uses Tera grass Ho-Oh, this thing becomes useless and you should hope something else on your team can handle it.
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