Some CrystalDiskMark results

Transcend SSD 370S 256GB

Sandisk Ultra 16GB

EMMC of iWork 1X

Micron black USB3.0 64GB

Sandisk Ultra Plus 64GB (USD$15 during Black Friday 2017)

Samsung Evo 64GB (SGD$28 or somewhere in early 2017)

Relatively new

After some usage