In addition to this, could someone test;
Other static healing such as Walrein's ability to heal from hail, dry skin in rain, ingrain, and aqua ring.
Healing as the result of a move like Drain Punch.
I've not had a chance to test it on the DS, but I found myself in an interesting situation on PBR the other day:
In the Little Cup, the level 5 max colosseum, I had a rain dish lotad out vs. a bronzor.
Turn 1:
Lotad uses Leech Seed.
Bronzor is seeded.
Bronzor uses Heal Block.
At the end of turn 1, leftovers healed Lotad and leech seed damaged Bronzor, but Heal Block prevented the seed damage from healing Lotad. I would assume Drain moves work the same way as this, but it could use testing.
Turn 2:
Lotad uses Rain Dance.
It begins to rain.
Bronzor uses Confusion.
At the end of turn 2, Rain Dish's effect indeed heals Lotad, along with the leftovers. The leech seed works the same way as it did on turn 1.
I would then assume that all abilities that have healing effects would heal through heal block, but it would still need to be tested on the DS. As far as Ingrain and Aqua Ring go, I have a feeling they would be blocked as they are moves, but that's just speculation. I'll try to test all of this on the DS soon.
A side note: I assume then, in regards to priority moves, that Avalanche and Revenge are indeed 'meant' to happen after Focus Punch. A crazy situation involving that happened while battling a friend not too long ago, and I struggled to find any information about it.
UPDATE:
I was able to test some of the other moves in question on the actual DS.
Aqua Ring and Ingrain both are prevented from healing a pokemon who is under the effect of Heal Block.
Leech Seed and Giga Drain / other draining direct damage moves all have their healing properties negated when the user is under the effect of Heal Block. They still do damage as normal.
Both Leftovers and Black Sludge heal regardless of Heal Block status.
When under rain, both Rain Dish and Dry Skin heal regardless of Heal Block status. I did not test Ice Body, though you would expect it to work the same way.
When poisoned, Poison Heal heals regardless of Heal Block status.
Note that I did not test Water Absorb, Volt Absorb, and Dry Skin in regards to healing when hit by the respective type moves while under the effect of Heal Block. I would think they still heal though, as it seems to be that Heal Block only blocks healing associated with actual moves - items and abilities that induce healing seem to work regardless.