Double Bird + Urshifu Rain
This is a team I built a long time ago, and is based on allowing Rain to patch up its worst matchups and make them a lot more playable, and thus make the playstyle a lot more consistent.
What it essentially boils down to is abusing the combination of Zapdos and Thundurus Therian for two factors, one of which being Thundurus' excellent matchup into bulkier teams, as well as its ability to overwhelm shared check with Zapdos, making it much harder to simply wall out rain.
The team does lack a Ground type, but that's because Thundurus Therian's Volt Absorb is already the Electric immunity, on top of their being a very sturdy Eject Button Ferrothorn to pivot in on and snag momentum from Electrics. In my opinion Rain can afford to bend the rules a bit in that regard because...come on look me in the eyes and tell me Seismitoed is a stopgap to Electric types.
Scarf Urshifu is here to provide both another pivot, specific defensive utility VS Tyranitar to offer more wiggle room with a double bird core, and a means to revenge kill threats outside of Rain without relying on Barraskewda as much.
Again, this is quite an old team, but I still quite like it and think while Zapdos on Rain is already great, there is a small bit of room for exploration on the structure to allow for facilitating it in its weaker matchups, with Zapdos and Thundurus combine helping to accomplish that.