Are there any legal glitches in Starcraft2?

This Mineral Boosting Trick is the only example I'm aware of and it's likely to somehow be patched out in the next version of SC2, as it's similar to a previous trick that was also patched out.

Blizzard no longer seems to be a fan of emergent gameplay and so these "tricks" that were so common in SC:BW are purposefully taken away.

Although Blizzard is not fond of glitches in general, the priority they give to mineral-walking (drones, SCV's and probes set to gather minerals) has led to some quirky scenarios. One of the most notable can be seen here.

Stephano was able to push the Dark Templars off of his Hatchery by mineral walking his drones so that they push the DTs, then having them hold position. This bought him vital time.