Check this thread for what we currently know first. If you are looking for new abilities, the first post should have most of them. If you are looking for changes to old abilities, hit Ctrl+F, and search for ***.
: Does it inform this Pokemon of super-effective Judgment or Weather Ball? Is Counter considered a Fighting attack, is Metal Burst considered a Steel attack, and is Mirror Coat considered a Psychic attack? How about Beat Up, Doom Desire, and Future Sight? Can you get the trait through Trace, Skill Swap, or Role Play and still have it warn you?
How to test: Use Sunny Day on a Castform with Weather Ball but no other move that's SE on Wormadam. Switch in Wormadam.
Give Arceus a plate that makes Judgment Super Effective on Wormadam (for instance, Flame Plate). Make sure Arceus has no other moves SE on Wormadam. Switch in Wormadam.
Send out a Pokemon with Mirror Coat, but no attacks that hit Croagunk / Toxicroak super effective. Switch in Croagunk / Toxicroak.
Send out a Pokemon with Future Sight, but no attacks that hit Croagunk / Toxicroak super effective. Switch in Croagunk / Toxicroak.
How to test Beat Up, Doom Desire, Counter, and Metal Burst is pending further testing of Anticipate's interaction with Skill Swap / Roll Play / Trace.
Switch in Porygon2 with Trace on a Croagunk / Toxicroak with a Fighting move.
Use Roll Play on Anticipation Pokemon with an SE move, for instance, Stantler Roll Plays a Toxicroak with a Fighting move.
Use Skill Swap on Anticipation Pokemon with an SE move, for instance, Blissey uses Skill Swap on Toxicroak with a Fighting move.
How does Unaware work with Clear Body?
How to test: Get a Pokemon with Clear Body to get a stat up that isn't in Speed. Bring in a Pokemon with Unaware. Example: Regirock used Curse. Trainer switched in Bidoof. Bidoof used physical attack that hits Regirock. Report damage.
What happens if the Defense and Special Defense are equal?
How to test: Switch in a Download Pokemon on something with equal Defense and Special Defense multiple times. If the same Pokemon ever gives a Defense and a Special Defense boost, it's random.
: What is the effect of two Pokemon with Flower Gift out at the same time on the same team? Is it one bonus, added bonuses, or multiplied bonuses?
How to test: Have a faster Cherrim use Sunny Day, then have a slower Cherrim use like 3 attacks on ally Cherrim. Report the damage, the defending Cherrim's Defense / Special Defense and the attacker's Attack / Special Attack (depending on what type of attack you smacked it with).
Does Hustle affect the Accuracy of Seismic Toss, Night Shade, Endeavor, or Dragon Rage?
Does it block the "recoil" of an enemy's Jaboca / Rowap Berry?
How to test: Use a physical attack on a Pokemon with a Jaboca Berry, or use a Special Attack on a Pokemon with Rowap Berry.
The new changes have been documented at http://members.shaw.ca/teamrocketelite/PickupTable.html
. Needs additional confirmation, but not a priority since there are only three changes.
A Poisoned Pokemon with Poison Heal still takes damage outside of battle.
Does Quick Feet work the turn Freeze and Sleep end? Does Quick Feet boost your Speed under Freeze or Confusion?
Does Reckless boost the damage from Struggle?
Does it block the damage caused by an opponent holding a Jaboca or Rowap Berry?
How to test: Get a Pokemon with Rock Head. Use a physical attack on a Pokemon with a Jaboca Berry, or use a Special Attack on a Pokemon with Rowap Berry.
Does Rock Head block the crash and miss damage from Jump Kick / Hi Jump Kick (wondering because of Reckless)?
I know it blocks stuff like Ice Beam's chance to Freeze and Fake Out's flinch, but does it also block stuff like Charge Beam's chance to raise Special Attack, or Silver Wind's chance to boost all stats (stuff that doesn't affect the Shield Dust Pokemon)?
Slow Start can be Skill Swapped away in English versions of DP and have the effect be removed, but not Japanese (Skill Swap works, but the effects remain on Regigigas).
If you Fling an item at a Pokemon that has Sticky Hold (and who is itemless), would it hold onto the item?
If a Pokémon with Sticky Hold Flings an item, do they lose it, or does it yo-yo back to them?
Is not activated by Flame Orb, Toxic Orb, or Toxic Spikes. Is not activated by any self-induced status like Rest.
Does it boost Struggle?
Do any moves, aside from Fire Fang, always hit through WonderGuard? Trace Gardevoir + Porygon2 would likely be the best way to test this.
Can Counter, Mirror Coat, Metal Burst, Sheer Cold, Fissure, or any other non-regular damage move hit through Wonder Guard if the type would render it super-effective? I think Night Shade and presumably Dragon Rage do.