Jirachi @ Leftovers
Ability: Serene Grace
EVs: 252 HP / 160 Atk / 96 Spe
Jolly Nature
- Iron Head
- Toxic
- Substitute
- Fire Punch
Landorus-Therian @ Leftovers / Soft Sand
Ability: Intimidate
EVs: 56 HP / 220 Atk / 232 Spe
Adamant Nature
- Earthquake
- Knock Off
- Rock Polish
- Swords Dance
This is a combo I played with during the most recent round of suspect testing. From my experience there, Sub + Toxic Jira does a good job drawing in and wearing down several of Lando-T's checks. For example, Rotom-W often tries to come in on Jira only to end up poisoned. Between poison and having its Leftovers removed by Lando-T's Knock Off, Rotom-W tends to get worn down very quickly, especially with SR up. Once this is done, double dance Lando-T is able to break through one of its biggest obstacles more easily. Aside from poisoning Rotom-W, Jira can also status Pokemon like Keld, who resists everything in its arsenal. Wearing down Keld via poison makes it easier to put it in range for Lando-T after, say, a RP. For similar reasons, Jira's ability to poison other things like Quag, Hippo, Slowbro, and opposing Lando-T is also appreciated by the core's own therian.
Besides the above, there are a few other ways these two work together. Jira's biggest obstacle is Tran, who Lando-T threatens nicely. Exca and Chomp are also annoying, and Lando-T's ground immunity helps greatly here. As mentioned with the Rotom-W example earlier, Lando-T can also Knock Off items from various defensive Pokemon (Skarm, Hippo, Slowbro, and so on). Removing potential Rocky Helmet's from some defensive Pokemon is also beneficial for Jira. All of this makes them easier for Jirachi to break through on its own. This works both ways, with Jira also being to wear things down for Lando-T as touched upon earlier. Because Lando-T can't always realistically set up both a SD and RP, certain Pokemon like Latios are still annoying depending on whether you're +2 in speed or attack. Jira's ability to check Latios and other Pokemon like Mega Latias, Kyu-B, and defensive grass types like Ferro thus proves useful.
Overall, these two are able to wear down certain obstacles for one another through several means, all while also being able to check a few important threats for each other. While known, the sets here aren't the most commonly used on Jira and Lando-T. They still remain effective however and make for a fun tag team.