For me it's these -

Doves - Winchester Texas Heavy Load, 12 ga, 2 3/4", 3 1/4 Dr. Eq. (1255 fps), 1 1/8 oz of lead #7 1/2s.

Those were about $6 or $7 a box at Bass Pro as a pre-season special. They were in limited supply and went REAL fast. In 12 ga out of a full or mod choke they have the reach for small high fast flying birds. And there's plenty of shot, which makes 7 1/2s a good alternative to 8s. I'm really sold on these.

Quail - two loads I like. Winchester 20 ga, 2 3/4", 2 1/2 Dr. Eq. (they don't list the fps), 7/8 oz, #7 1/2 lead shot. And, Remington 20 ga., 2 3/4", 1225 fps (they don't list the Dr. Eq.), 7/8 oz, #7 1/2 lead shot.

This is very close range shooting and a pellet or two is enough, so 7/8 oz out of a 20 ga is plenty good IMO. I like the 7 1/2 better than 8s not just because of more pellet energy but because it blows thru better and not as much of it stays in the bird and therefore you don't wind up chewing on as much shot. I like 6s even better for that reason, but then your pattern can be a bit sketchy if the bird gets on away from you (although I have used 6s on pen raised birds with no downsides).

The Win and Rem I think are about equal. As of yesterday they were both $7 a box at Bass Pro. So which do I buy? Both. Maybe a case, with 5 boxes of each (to spread the wealth around - oops, that didn't sound right, did it?!?)

Ducks - I use steel. It is or at least was cheaper and most importantly I bought a big supply of it when it was about $10 a box. I use either of these two loads depending on whether over decoys or passing shots -

Over decoys - Winchester Drylok Super Steel 12 ga, 3", Magnum Dr. Eq., 1 3/8 oz, #3 steel shot.

Pass shooting - same except BB steel shot.

You used to find these on sale after duck season for half price. I have boxes bought in different years marked $10, $14 and $17 and as of yesterday they had it for sale at $23. Fortunately I've already got enough.

I had to dig deep into the old ammo magazine/closet for these and I hope some here find the recommendations helpful.

This so far has been a real good year to be a wing shooter.

Doves
20 Gauge
7/8 oz
8 shot lead (works up to 65 yards)
Mod Choke

Quail
28 Gauge
3/4 oz
8 shot lead (works up to 40 yards)
IC Choke

Ducks - Puddle
20 Gauge
7/8 oz
4 shot non-toxic (works up to 30 yards - decoying birds)
IC Choke

Ducks - Divers
12 Gauge
1 1/4 oz
4 shot non-toxic (works up to 40 yards)
Mod Choke

Ducks - Seaducks
12 Gauge
1 1/4 oz
4 shot non-toxic (works up to 40 yards)
Mod Choke

Geese - Decoying
12 Gauge
1 1/4 oz
4 shot non-toxic (works up to 40 yards)
IC Choke

Geese - Pass Shooting
12 Gauge
1 1/4 oz
BB shot non-toxic (works up to 60 yards)
Patternmaster Choke

DOVE LOADS -- It doesn't take much to kill a dove, just a couple of pellets in the front end will do it. I like #8 lead or #7 steel to maintain good pattern density particularly in these 20ga loads. If you like a 12ga then a 1oz load of lead #7 1/2s or #6 steel is hard to beat.

20ga 7/8oz #8 magnum shot @ 1,200 fps (reloads)
O/U with IC/F chokes
30 yard pattern IC / 237 (69%)
40 yard pattern F / 226 (66%)
or
20ga 3/4oz #7 Rem Sportsman steel @ 1,425 fps
O/U with SK/IM chokes
30 yard pattern SK / 248 (76%)
40 yard pattern IM / 223 (68%)

QUAIL LOADS (over pointing dogs) -- Quail are a little larger that dove and most shots are going-away so I prefer to up the pellet energy a little to provide better penetration over the dove loads although they will also work at close ranges.
20ga 1oz #7 1/2 Rem Sureshot @ 1,165 fps
O/U with CYL/M chokes
20 yard pattern CYL / 306 (88%)
30 yard pattern M / 298 (85%)
or
20ga 3/4oz #6 Win Xpert steel @ 1,325 fps
O/U with CYL/M chokes
20 yard pattern CYL / 191 (80%)
30 yard pattern M / 182 (75%)

DUCK LOADS (over decoys) -- Duck just aren't that hard to kill if you get them close and put the patten on their front end.
12ga 2 3/4" 1 1/8oz #4 Rem Sportsman steel @ 1,375 fps (small or close duck shooting)
O/U with SK/M chokes
30 yard pattern SK / 176 (81%)
40 yard pattern M / 159 (73%)
or
12ga 2 3/4" 1 1/8oz #2 Rem Sportsman steel @ 1,375 fps (mallard shooting)
O/U with SK/M chokes
30 yard pattern SK / 116 (84%)
40 yard pattern M / 114 (82%)

GOOSE LOAD (over decoys) -- I like be ready for a little longer shot at geese than ducks, hence the 40 and 50 yard patterns.
12ga 3" 1 1/4oz BB Rem Sportsman steel @ 1,400 fps
O/U with IC/LF chokes
40 yard pattern IC / 61 (72%)
50 yard pattern LF / 60 (71%)

I find these loads/chokes work just fine for my hunting/shooting. After all, if you can't put the pattern on the front end of the bird, then little else matters!!!

Good luck.