Hi Jimmy,
there are newer guidelines, see:
and etc ...
They aren't in a directory as they were until 2016. I can't tell you why the format change happened, I wasn't around at that time.
Anyway, new guidelines are still created approx twice a year. Add-ons guidelines have been recently added as well, which refstack server presents too (see OpenStack Marketing Programs list):
Currently there is an ongoing effort to make sure that we track all the relevant tests. We have also reached out to the teams during the Xena PTG and were asking if there are any new tests worth being included in the next guideline.