A distant memory
I disagree with this assessment. Tsareena has more good matchups than Olivia/Hapu. Maybe not natural as in "I win itemless," but they are still there:Steenee -> leaning towards D
This one is probably a bit more controversial, since Tsareena's movepool is actually quite interesting. However, this thing has numerous issues that I personally couldn't just ignore. First, the Steenee period is awful and you want to use this thing so it levels up faster. While you could switch train, this is rather annoying and also wears your team off a lot faster. Secondly, Tsareena has very few naturally good matchups, which are Olivia and Hapu, for most parts, with occassional kills with coverage here and there. Thirdly, the movepool, despite being varied, simply isn't too useful for when you get it. I'd honestly have put this in E if it wasn't for Trop Kick being nice utility, but all in all, Steenee was mediocre for me. I *could* push it to C with strong support, but for now, I'd need good arguments to raise this beyond D.
- Guzma is a fight that it can solo despite the natural type disadvantage. This is because Queenly Majesty (gotten from Oblivious Steenee) reduces Golisopod's options (that can hit you) to just Razor Shell, whose defence drops can be nullified with a Guard Special, X Defend, or even a Trop Kick. It needs an X Speed and a couple of X Attacks at the very least, but Golisopod being exploitable makes it doable in a reasonable timeframe (albeit item-assisted). The attacking move of choice is Acrobatics, which you can't get before Guzma 1, but you do get before Guzma 2. For Guzma 1 you could just Fling on Masquerain (More on Fling in a bit).
- High Jump Kick comes in time for Trial Captains, which gives Tsareena a really good option for Ilima, Sophocles [Ultra Sun], and Nanu [Ultra Moon]. It is also a useful option against Molayne and Olivia. Furthermore, Acrobatics is good for Mallow [Ultra Sun], and Lani [Ultra Moon] is an okay matchup with STAB and Acrobatics for Araquanid.
- Fling + one of the free fossils seems like a meme at first glance (Fling is obtained at Hau'oli Cemetery at night after getting the Ride Pager), but it should be noted that items flung in a trainer battle return to the Pokémon after the fight is done. This ends up having a few useful applications, like against Faba and Acerola, or even Hau's Raichu. Steenee can also learn Fling, which gives it something to hit things with at the very least, even though it can only do it once a fight.
- And then of course, there are some of the (mandatory) field trainers. Veteran Heather's Talonflame sucks, but Wailord is a good matchup, and Glaceon falls to High Jump Kick if you get it before then. Once you get past Eric's Noctowl, Gengar and Slowking fall to Fling and STAB, Fling deals with Yuki's Marowak, neither of Harry's Pokémon enjoy a Fling, Ace Trainer Jada doesn't like High Jump Kick into Fling.