A commission-like project for my friend's Harvest Moon MMO-thing going on.
While this is a work in progress, I guess it's a bit different of a work in progress--everything in this is finished, I just obviously don't have all of the items yet.
20x20 boxes show the size limits, and are intentionally left as the color they are for contrast against the white border for each icon.
Still working on this, and I'll update this as I go along.
...Umm...as for the color count, obviously each item has their own colors...that may take a long time to count, trust me. I'd approximate 4-5 or more colors per icon. | 
Yeah, you do have a good point there; there are quite a few colors that are incredibly similar.
If it weren't for the fact that these are just for a web site instead of an actual programmed game (whether it be a game made with Java, Flash, a ROM hack, whichever), I would likely not hesitate with fusing the similar colors together. However, since it's for a rather simple MMO (as of now) that probably won't go very far, I most likely won't bother myself too much with doing so.
However, I greatly appreciate your constructive feedback and I will definitely keep it in consideration for any future projects I start on. =3