I did get a Wurmcoil Engine out of the SOM Booster Box

I also pulled a second planeswalker: not bad. The completion percentages for this large set are:

3 packs       17.90%
9 packs       41.92%
15 packs    59.83%
24 packs    72.49%
30 packs    79.04%
36 packs    84.28%

It looks like for this booster box 24 packs is when completion saturated.

Here is a foil Sylvok Replica.

Here is the rules tip card for Infect.

I am now missing 14 of the 88 artifacts in this set.

Elspeth Tirel planeswalker.

Some non-artifact uncommon and rare.

...and last, but not least, a token.