Ok, the reason I'm asking is a few of these places are either difficult to manage in Spanish or they spit in guiri food. Annotated accordingly:
Based on some dozens of meals, O'Pazo is the most consistent and pleasant of the seafood places. It's possible to spend much too much there if you must have angulas or percebes (and of course you must avoid Chambo's amateur move of getting cigalas), but to me a meal of media de pulpo, media de salpicon, two carabineros, some camarones de la ría or another small seafood item, whatever fish they recommend (al horno is their strongest for rodaballo or merluza, they also do a mean sole, and grouper if they have it) - but not the composed entrees, with maybe some oysters for dessert is terrific and the price is just funny. Of course there's nothing wrong with the langosta, centollo, etc. Belondrade y Lurton, Chivite 125, Cvne Monopole (I know someone asked recently about the clasico, but iirc this is just the regular young one), and many other options for wine.
Sacha - you'll get a vaguely suspicious vibe here as a first timer, but they are in fact very nice and the recently promoted maitre d' speaks good English. Order too much and they'll edit you down. The menu is divided into old standbys, dishes of the day, and other classics, although I've seen dishes move between sections on consecutive visits (and here I should admit we were here three times in two weeks). Many legendary items by now including the navajas in very long cooked garlic, the tuetano and its side of steak, the falsa lasaña of crab or uni, the mollejas, whatever incredibly delicate vegetable prep they have... many people like the tortillas although I've never had them. wine list is mostly conservative, but super cheap and with many good options. Tocin(ill)o del Cielo for dessert. Not quite as seasonal as his peers, for better or worse.
La Tasquita de Enfrente - this is a tough one - the ingredients are the best in spain and allow Juanjo to do things that are otherwise risky, like his dish of squid with its not particularly cooked innards - but he just doesn't care about tourists at all. You'll probably be referred to an underling and you'll need to insist on getting read the full list of specials... anyway, it's not an easy place to recommend but the food is very good if expensive for Spain. I don't like the wine list at all. (eta: perhaps a good way to mitigate the issues is to ask in advance for a tasting menu and price it somewhere above their base amount). Juanjo opened a sandwich shop right next door which is excellent for a quick lunch snack.
La Buena Vida - husband and wife team, terrible room (don't feel like they gave you a bad table because there are no good ones). The regular menu has nothing on it that you care about except maybe the raya a la mantequilla, and the dishes on it are cooked by an assistant - everything you want to order is a special (prices offered). Again I recommend over ordering and being edited down (most things available as medias). Very good wine list. Hard to recommend specific dishes as they're very seasonal.
Alabaster - disclosure - we have some business dealings with their group and have had dinners going on until 3am on occasion, but regardless it's a very good place with strong galician roots but a modern and exceptionally well run kitchen given the size of the place. The merluza is tops, and if they have the percebes in salt and seaweed that's a must, at least once. Very good wine list.
Horcher - a most ridiculous place, and expensive, and very set in their ways (including illegally adding vat to menu prices) but you come here for three things - the duck press (in season, the grouse press, or the becada press), the stroganoff (in season the corzo stroganoff), and the rapidly diminishing list of old riojas. But you should go before the wine is all gone. Jacket required and a tie can't hurt.
Santceloni - keeps to the tradition of Can Fabes, but increasingly you can feel the hotel is taking over (including jacking up wine prices to tourist restaurant levels) and our last visit was the first where I felt no need to return soon. Still easily a two star restaurant and if you compose your own meal from 5-6 dishes (everything can be split in two) you'll eat well, and cheese of course, lotsa cheese.
Nakeima - in theory there's a menu but in practice you sit at the bar and eat the same tasting menu as everyone, with wine pairings. We had a couple of very good meals here and one that was still good but less interesting. Something of a nuisance as you need to show up early and wait in line just to get your name on the list but if the weather is nice then why not. The time between getting your name in and dinner is well spent at El Atomico on the next block west.
Taberna Verdejo - many excellent dishes - their house salt cured meats and fish, the escabeches, game dishes... good wine "list" (in the sense that you give them an idea and they will offer you options) with a particularly good nose for oxidated wines. The couple who run the place are the nicest people ever.
Desencaja - the decor reminded me of Tides in nyc, and not in a good way, and with the very low prices I was worried, but actually the food was very good, including this sort of stuff:
The group is loving Arima but we haven't been yet. AskuaBarra worth a mention for their superb steak tartare and ear terrine, although the chuleta left me unimpressed.
I'll add more later.
p.s. Punto MX have switched to a tasting menu only format, which people are very unhappy with, and this follows a long process of menu simplification and price hikes. They still serve the good old dishes at their bar, but it is a very unpleasant environment. We had very good tacos at Mawey, but not a full meal and I don't feel confident recommending it yet.