[Samsung Galaxy Note 9 Questions & Answers] 6thtry:
Okay, cards (and other stuff) arrived and tested. Combining most of my previous results into this reply for easier comparison. All cards have been given at least two runs, to notice possible exceptions/failures and to get an idea of how much there could be random variance between runs with the same card. AndroBench test settings were defaults, except the target was changed to whatever non-internal target was available, and run the "micro" test, not bothering with the SQLite test.

(Edit: all Samsung cards were measured directly after taking them from their packages, i.e. as empty as they can be. The Sandisk card was otherwise as new, but I took few test photos before running AndroBench.)

Phone model is, as far as I can tell, SM-N960FZBDNEE, (128GB, dual sim, Exynos).

Between the Samsung cards, the differences between cards of the same size are smaller than differences between test runs, so I'd say it is safe to assume that Evo Select is indeed just Amazon's rebrand of Evo Plus. Note how the sequential speeds are pretty much the same for all of them, even if the advertised numbers have lower write speeds for 64GB models. That is, seems that the phone is mostly the limiting factor. Note also how 64GB models have a bit higher random read IOPS rates than the 128GB models of the same series.

Tested cards and their advertised ratings:

Sandisk Extreme Pro 128GB . . . . (UHS-I 3, 170MB/s // 90MB/s, V30, A2)

Samsung Evo Plus 128GB . . . . . . . (UHS-I 3, 100MB/s // 90MB/s, no Vxx or Ax ratings)

Samsung EVO Select 128GB . . . . (UHS-I 3, 100MB/s // 90MB/s, no Vxx or Ax ratings)

Samsung EVO Plus 64GB . . . . . . . (UHS-I 3, 100MB/s // 60MB/s, no Vxx or Ax ratings)

Samsung EVO Select 64GB . . . . . (UHS-I 3, 100MB/s // 60MB/s, no Vxx or Ax ratings)

Exact product/model codes:

Sandisk Extreme Pro 128GB . . . . SDSQXCY-128G-GN6MA

Samsung Evo Plus 128GB . . . . . . . MB-MC128GA/EU

Samsung EVO Select 128GB . . . . MB-ME128GA/EU

Samsung EVO Plus 64GB . . . . . . . MB-MC64GA/EU

Samsung EVO Select 64GB . . . . . MB-ME64GA/EU

Results

Single run, "best" of those whose values I recorded. Comments note about significant differences with the same card in my Tab S3 (which, afaik, has Snapdragon, not Exynos), or about an exceptional value.

Sandisk Extreme Pro 128GB

Sequential read 72.65 MB/s

Sequential write 48.02 MB/s

Random Read 5.8 MB/s, 1487.3 IOPS (4KB) -- can reach about +20% on Tab S3

Random Write 2.44 MB/s, 625.48 IOPS (4KB) -- can reach about +10% on Tab S3

Samsung Evo Plus 128GB

Sequential read 66.63 MB/s

Sequential write 39.13 MB/s

Random Read 4.93 MB/s, 1264.39 IOPS (4KB) -- can reach 8.33 MB/s, 2134.87 IOPS on Tab S3

Random Write 2.6 MB/s, 666.85 IOPS (4KB) -- can reach about +10% on Tab S3

Samsung EVO Select 128GB

Sequential read 66.55 MB/s

Sequential write 39.14 MB/s

Random Read 4.76 MB/s, 1221.01 IOPS

Random Write 2.38 MB/s, 609.29 IOPS -- Note, another run got 2.63, 674.92

Samsung EVO Plus 64GB

Sequential read 69.64 MB/s

Sequential write 37.23 MB/s

Random Read 6.42 MB/s, 1644.28 IOPS

Random Write 2.68 MB/s, 686.8 IOPS

Samsung EVO Select 64GB

Sequential read 72.18 MB/s

Sequential write 37.35 MB/s

Random Read 6.27 MB/s, 1606.38 IOPS

Random Write 2.76 MB/s, 708.04 IOPS

(Especially last one, quite different from what hankvb was getting with his unit. Perhaps Snapdragon vs. Exynos difference? Repeating his results here for easy comparison:

Samsung EVO Select 64GB

Sequential read 84.93MB/s

Sequential write 70.71MB/s

Random Read 8.59MB/s, 2201.15 IOPS (4KB)

Random Write 3.3 MB/s, 845.25 IOPS (4KB) )

So, all in all, I'm still inclined to blame the phone and/or its firmware/drivers, for the (s)lowish results, not the cards.

Sandisk goes back in, for its highest sequential speeds.