Here's a core that I have been using lately with a pokemon that is very underrated but goes well with the other 2 mons.
Seismitoad is a very underrated hazard setter with a great defensive type as well as a outstanding ability, being immune to water attacks. With seismitoad partnered up with banded bulu, it complements each other very well. Seismitoad completely walls mons like heatran, Rotom-Wash, zapdos, tapu koko and charizard x. But with the addition of grassy terrain on the field, it walls mega swampert, Landorus-Therian, and offensive garchomp. On top of that seismitoad gives tapu bulu some slack on switching in on ash greninja due to its water absorb ability. celesteela+seismitoad also has great type synergy, as seismitoad counters a good amount of celesteela's checks, and steela checks the grass types/ psychic spam that threatens toad.
Seismitoad is a very underrated hazard setter with a great defensive type as well as a outstanding ability, being immune to water attacks. With seismitoad partnered up with banded bulu, it complements each other very well. Seismitoad completely walls mons like heatran, Rotom-Wash, zapdos, tapu koko and charizard x. But with the addition of grassy terrain on the field, it walls mega swampert, Landorus-Therian, and offensive garchomp. On top of that seismitoad gives tapu bulu some slack on switching in on ash greninja due to its water absorb ability. celesteela+seismitoad also has great type synergy, as seismitoad counters a good amount of celesteela's checks, and steela checks the grass types/ psychic spam that threatens toad.