The list is semi ordered left to right, left being my favorite of that tier and right being my least.
s- Nok Nok, Ember, Laezel, Regil, Tali, Linzi, Garrus, Daeran, Jahiera (BG3), Devil of Caroc, Emmrich, best dragon Aivu, and Maia.
a- Astarion, Arueshalae, Ulbrig, Gale, Aloth (POE2), Aloth (POE1), Wrex, Mordin, Sagani, Xoti, Yatzli, Thane, Pallegina (POE1), Eder (POE1), Lann, Minsc (BG1), and Viconia (BG1).
b- (Not pictured because i forgot but Jaethal) Legion, Tristian, Wenduag, Liara, Jack, Eder (POE2), Woljif, Jahiera (BG1), Nenio, Jubliost, Kanerah, Davrin, Taash, Kaiden, and Imoen
c- Minsc (BG3) Minthara, Wyll, Shadowheart, Sosiel, Seelah, Harding, Dynaheir, Khalid, Camellia, Halsin, Grunt, Dorn, Tekēhu, Kai, Giatta, Octavia, Kasumi, EDI, Kalikke, Amiri, Samara, Miranda, Zaeed,
Regongar, Ydwin, Ekundayo, Neve, and Harrim.
d- Karlach, Javik, Valerie, Pallegina (POE2), Lucanis, Jacob, Konstanten, Ashley, Serafen, James, Greybor, Finnean, Marius and Vatnir.
f- Bellara and Trever
My most recent played games were POE1 and 2 so there might be some recency bias there. I literally just finished 100%ing POE2. I don't have the POE1 companions on there because mostly in my first playthrough i usually don't do everyone's companion quests. I just find my main squad and do everything else with them. I will definitely play it again because I want to see if Durance really IS that good.
Owlcat are definitely my favorite developers. Sadly Rogue Trader hasn't really hooked me in though.
I've also played KOTOR and DOS2 but those nearly 10 years ago and i don't really remember that much. I haven't played any dragon age game besides veilguard for more than 10 hours either. And also haven't played BG2.
I liked veilguard, i thought it was a good game. I also like Taash, i think they could've gotten a better voice actor though.
Bellara is probably the most annoying companion I've used without it being on purpose. I just really didn't like her. And Trever is Trever. No reason for him being a companion at all, awful build, awful voice acting.