I think Arctic Char would fit in here, and steelhead...salmon, of course comes in a range of varieties, chum, keho, coho, sockeye, Atlantic, Scottish, farmed or wild for all of these...
I find smallmouth bass to be the "oiliest" of them all (maybe that's just me being me?) but its doubtful you'd find that in a store...you have to catch them yourself...
I've said it before, I like fresh garlic, chopped up...and with salmon only, lets add some sea or Kosher salt, some fresh pepper, the herb and garlic marinade...I've never tried any pre-made mix of spices and oils to hold until I did a fish, always made up my marinades or rubs off what was on hand...
A lot of respondents here like their fish distinctly "underdone" from what we like, and I imagine, again, that this may be because they use lemon or "seasoned rice vinegar" (golly, is that ever a handy condiment!) as a feature in their marinades...if you head in that direction, you could, I guess, use some form of tobasco seasoning in the marinade and eliminate the fresh ground pepper, and slash the skin and insert garlic cloves, but "wet" fish is not to my liking...what's left of a good salmon fillet can be mixed up into tonight's or tomorrow's salmon salad sandwich....
I wouldn't say "No" to trying out Basil, Rosemary and Marjoram with salmon, and olive oil comes through for me, as did butter before lactose intolerance crept into the family and chlorestral went through the roof...
Note that Lake Trout can be reasonably "oily" too, depending on where they are sourced from (where I fish, they can be quite "pink") and a lot of the salmon technique can be applied to them...
For tuna, I buy only the fresh steaks, and prepare them as if they were beef...cooking on the hottest heat with Hy's seasoning and olive oil for about two minutes a side (an epicurious buddy asked why I liked them "well done"?) and they come out like a good filet mignon...hard, in fact, to tell the difference....
