Just wanna share some of my opinions based on 200+ battles in the ranked class, my team goes as follows:
Arcanine
Goodra
Volcarona
Umbreon
RotomW
Gallade
I wanna start by saying Arcanine is an incredible user of intimidate and my #1 most unpredictable pick with a fairy terra coupled with play rough to counter the dragon heavy meta makes it a serious threat to a lot of teams I encountered. I chose close Combat over wild Charge for coverage because of the ability to 2hko gargancl on the switch. Extremespede makes it amazing at both revenge killing and taking away focus sash, always works on meowscarada and even palafin to set up against the flip turn to catch them off guard. Fire is incredibly good against a lot of threats like kingambit and gholdengo and flare Blitz will get the ohko every time. Hands down super underrated pokemon especially when you have great offensive and defensive terras at your disposal.
Second, assault vest on Goodra makes it a super oppressive special wall against almost all the special threats in the meta that aren't dragon when you don't consider terra types. The only mons who can deal with acid spray+coverage move is steel types and if they give you trouble it has access to fire blast/flamethrower. Considering my team I opt for Poison terra to counter fairy Rotom, azumaril, and even play Rough meowscarada. It's always safe to switch into rotom, handles walls like gargancl, dondozo, and even clodsire by neutralizing thier special defenses either on the switch or by eating a move or two. Goodra has won me many matches because it was taken lightly, and the ability gooey usually forces them to switch out after knocking goodra out because they will be outsped.
And third, umbreon is more of a niche counter to a lot of threats when used correctly. Ghost terra typing is what absolutely shuts down Dragonite, Maushold, and drain punches that can be seen from a mile away. Baby doll eyes is what I use instead of protect because it can help wall out even supereffective hits and help it eat u-turns. Thunder wave is always detrimental to any set up pokemon or even walls, moonlight and leftovers make it really hard to get off the field, and foul play makes it great against all the physical threats.
Again, this analysis is after hundreds of matches, not all of them were wins of course but most notably I did exceptionally well against teams that used a lot of the mons rated so highly like Palafin, Hydreigon, Breloom, Espathra, just to name a few. I think unpredictability goes a really long way in this game with terra types being a thing and in a competitive scene somehow people forget to think outside the box a little bit.