7. Flurrie - She's situationally useful if you're fighting a bunch of weak enemies at once or trying to knock an enemy off the ceiling. Other than that I didn't really use her that much outside of when it was necessary to progress the story.
6. Bobbery - He's good during the part of the game immediately after you get him and against the Dull Bones/Dark Bones in the Palace of Shadow. Outside of that, he never really did anything for me that other companions didn't already do.
5. Ms. Mowz - A lot of people put her last because she's the optional companion and has relatively low health, but I think she's the best partner in terms of the ones that are "situationally useful". Her main attack ignores defense, so she's great to pull out whenever you need to fight something like a cleft or a chain chomp that have defenses of like 3 or 4, especially in the late game.
4. Koops - He has a great attack to hit all enemies not in the air that doesn't cost a ton of FP, and is the only partner that has a defense of 1 so he's a bit more tanky than the others. I also remember all of his action commands being ridiculously easy so there's almost no chance you fuck up and miss or something.
3. Yoshi - I feel like a lot of his attacks are all-around decent and (iirc) relatively cheap to use? Gulp in particular is also useful against enemies with a high defense. A lot of hardcore TTYD fans have definitely made videos about how he's one of the easiest companions to exploit and make the game super easy (which isn't even necessary, the game is already easy lol).
2. Vivian - Fiery Jinx is always a go-to, does a lot of damage relative to the point in the game when you get access to it and hits every enemy at once while also burning them for additional damage over time (often saving you a turn or two). Veil is also a must-have for newer players because it allows you to avoid the "charged" boss attacks from Gloomtail/Shadow queen that do ridiculous amounts of damage.
1. Goombella - Hands down the most broken and overpowered companion in the game, letting her get below 5 HP (while having Power Rush equipped) while charging her attack and then using multibonk basically ends up being an instakill on almost any boss. I also love that her partner ability is a different piece of unique dialogue for every single loading zone.
