For now, we have these:
1. Seven deadly sins
2. Crafting Materials (tech-able? needs clarification from NFWar
)
3. Books (kinda missed this one at first, but we sure could use some book icons to replace ladder ones)
4. Building upgrades and techs
5. Vegetables
6. Mirage - reversal of a ladder icon
7. Item sets (Personal fav)
8. Elemental Skills/Items
9. Aura Icons
10. Classical tech upgrades (3-sword, 3-shield, 2-caster and such)
...tho we can merge #4 and $10 in one, making it a rounded versatile and anything Techtree-able as an icon set.
I'd also like to add these for commenting could they be possible themes:
11. Orbs
12. DotA skillset re-vamp (don't hate me for this one, but DotA comprises around 100 of heroes of which any you could pick and make new icons for his/her skills, which is a fantastical and versatile base)
13. Command Icons (Attack, Patrol, Move, Hold Position, Stop (Optional: Learn Skill, Cancel))
By the way, this is not just a thread to post ideas. I'd like you to tell me what you don't like, and why, so that we can narrow the selection in the end to around 10 most creative ideas at maximum.
Btw, poll should be a multi-choice.