Can Zoroark's "Foul Play" attack use Medicham's "Yoga Loop" attack to repeatedly get extra turns?
Yes, Foul Play on Yoga Loop could work infinitely, if you're able to pull it off!
Source: TPCi Rules Team (2021-09-23)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH7_83
SWSH7_83
BW1_71