Right now you can get items from one of four ways:
Monster Drops: Low Quality
Gambling: Low-High Quality
Quest Rewards: Med-High Quality
Crafting Recipes: High Quality
What I am trying to think of is lots and lots of affixes so the items are as diverse as possible, I would be very grateful if people chip in with their ideas or provide links to websites that already have this. Here is what I have so far:
Combat
Poisons enemies – infested terran death for X seconds on singular unit
Flame affix – vulture spider mine on single unit
Lingering Flame affix – vulture spider mine for X seconds on fixed location
Ice affix – scarab death, with frozen unit for X seconds
Lingering Ice affix – scarab death, with frozen units for X seconds on fixed location
Ice Nova - multiple scarab deaths directly on top of player
Lightning affix – high templar attack and death, spreads to X nearby units
Decoy – spawns a hallucinate
Confuse – enemies ally with you temporarily
Support
Crits Per Minute (CPM) - for all weapons, since I don't use Upgrading or VHP
Evasion Chance - for shields, armour - basically it flickers invulnerability
Mana regen rate
Mana Restorative – trigger set vespene
Mana leech – each kill gives X mana
Spell Refund
Incremental Health boost – medic for X seconds
Health Restorative – trigger set HP
Death Exemption % – instant respawn, no gold deduction, no loss of companions, boss battle respawns
Increased EXP from monsters
Increased loot from monsters - gold, item drops
Specializations
Increased ore extraction – can mine twice before ore moves. Increase to thrice?
Enhanced aether extraction – quick time events are easier, portals spawn more frequently
Critter lure – lures critters to the player
Crafting refund – some or all materials are refunded when crafting
Miscellaneous
Team Player – increased output when in proximity of others, scaling from 2 to 3
Night-time – vision increased during night.
Summon burnout – decreased or removed entirely (summons last until their demise)
Summon time – decrease time it takes to bring in your summons
Companion distance – they can move further from you
Carry limit – amount of items you can carry, utility belt, crafting materials, equipment