Variations refer to having the same set in other design styles. This is one of the criteria we follow when approving icons on Iconfinder.
Creating the same icon set in several different styles can be a good idea in some cases. However, icon designers should be careful to not create too many variations of the same set, as that will clutter up the search engine.
How many variations are allowed?
Iconfinder will accept 1 variation of icon sets in each major icon style. By "major icon design style" includes glyph (solid), line, flat, 3D, skeuomorphic, cartoon, hand-drawn, and pixel.
Let's say you have an icon set of "tools" (hammer, wrench, drill, compass, and pencil with ruler). You can draw each of the icons in each of those styles and submit them. So, you could submit seven versions of each object (1 hammer in glyph, 1 hammer in line, 1 hammer in flat, 1 hammer in flat, etc).
We will not accept icon sets that use the exact same designs from above and simply place them on top of or inside of a colored or outline shape (circle, square, hexagon, etc). Please note, you can submit icons on top of or inside of a shape, but that will be considered your one variation. So, you cannot then submit the same icon without the shape. Our suggestion is to not submit icons on or in a shape unless the shape is integral to the design.
Please note, you do not have to limit yourself to just these four styles. You are free to do hand-drawn, cartoon, 3D, and/or skeuomorphic. This rule is to cut down on the number of nearly identical icons (such as doing a line icon then putting the exact same icon in a circle, a square, and a hexagon, then doing different colors of each shape). These variations do not qualify as different icons, but just a minor decorative change.
However, if you want to do an icon of, say, a power drill, and do a glyph version, a plain line version (no color), a color-filled line version, and a flat version that would be 100% okay. But taking that same drill in a single style, such as line, and doing a green line version, a black line version, a blue line version, then putting the same line icon on a black circle, a green circle, and a blue circle is not ok.
Allowing designers to submit unlimited variations of the same icons in this manner clogs up the search results with only the work of a single designer and limits the amount of variety a customer sees.
Unneeded gradients and color fill variations
In case of using gradients, there are cases when these gradient variations are not adding value to the icon, especially when the icon is in glyph or outline style. It does not add to the usability of the icon nor to its versatility. Additionally, gradients are difficult to edit if customers want to change the colors. Many customers would prefer a normal black fill or color fill, where they could easily change the colors.
The same applies to outline sets, when uploading in a normal color, users can change that quickly and apply it to the projects they are working on while with gradient that complicates things a bit.
Uploading these kind of variations also clogs up the search results with the same icons.
Read about all the other Criteria for approving icons.