Every icon library leads with a number. Ours says 13,332. That number is doing almost no work for you, and we can show you why using our own data, so here it is.
This week we pulled every record out of our own public API, all 13,332 of them, and counted what is actually in there. Not how many files we host, but how many different things a designer can pick from, how much of the library is the same object rendered again in another colour, and where the depth actually sits. The answer changed how we describe our own library, and it gives you a short test to run on any library before you commit to one.
What we pulled, and how
The icon endpoint pages at up to 1,000 records per request, so the whole library comes down in fourteen calls: api.thridy.com/api/icons?limit=1000&page=1 through page=14. We ran that on 2 September 2026 and got 13,332 records carrying 13,332 distinct ids. No pagination overlap, nothing missing.
Every record carries a name, up to three categories, keywords and three asset URLs. For the image comparisons further down we also downloaded 369 files from cdn.thridy.com: both halves of 60 matched pairs, plus 250 icons drawn at random from the full list. Every figure below came out of that session. None of it is quoted from anywhere else.
13,332 records, 5,231 nouns
First result, and it is a good one: all 13,332 names are unique. Not a single name repeats. We expected a handful of collisions across a library this size and there were none.
The second number is the one that matters. Take the last word of every icon name, which for "Black Forest Cake" or "Vintage Film Camera" is the thing being drawn, and you get 5,231 distinct nouns. Of those, 3,201 have exactly one icon behind them. That is 61.2 percent of the nouns in the library.
The last word is a heuristic and we want to be straight about it. It reads "Red Sports Car" correctly and misreads the 115 names, 0.9 percent of the library, that contain "of" or "the" or end in a digit, like "Bag of Rice" or "BYD Atto 3". We are using it as a measure of variety, not as a precise census, and at under one percent error the shape does not move.
So the library is not 13,332 choices. It is roughly five thousand things, most of them present exactly once, plus a smaller set of things present many times over. Aardwolf is one icon. Alan Turing is one icon. Marketplace is one icon. When your search lands on one of those 3,201, the result you get is the only result there is, and if the pose or the palette is wrong for your screen, there is no second option behind it.
Three quarters of the library has a sibling
Now flip it around. 10,131 icons, 76.0 percent of the library, share their noun with at least one other icon. The depth is real, and it is very unevenly spread.
Thirty-six nouns carry 25 icons or more, and between them they account for 1,648 icons. The deepest are face (100), flag (89), avatar (73), machine (71), woman (67), kit (63), mask (60) and box (60). Another 167 nouns hold between 10 and 24 icons each. Below that, 1,444 nouns hold two to four, and then the long tail begins.
This is worth knowing before you plan a screen. If you need twelve emotional states for a feedback widget, there are 100 faces and you will be fine. If you need one folder icon and one database icon for a file browser, the library holds five icons with "folder" anywhere in the name and exactly one with "database". Depth is not a property of a library. It is a property of the specific noun you happen to need, and the headline count cannot tell you which of the two situations you are in.
1,382 icons are the same object in another colour
1,484 of our names start with a colour word. For 1,382 of them, 10.4 percent of the whole library, the plain version also exists as its own separate icon: "Black Car" and "Car", "Blue Headphones" and "Headphones", "Brown Trowel" and "Trowel".
We wanted to know whether those are genuinely different renders or one file under two names, so we took 60 of those pairs at random, downloaded both 200 pixel WebP files from our CDN, and compared them. Not one pair was byte identical. Across the 60, the mean colour of the opaque pixels moved by a median of 39.8, on a scale where the largest possible distance in RGB is about 441, and the shapes differed by a median of 11.5 bits on a 64 bit perceptual hash. These are separate renders, not copies.
They are also, in a meaningful share of cases, barely different. In 21 of the 60 pairs, 35 percent, the colour moved by less than 25. Eight pairs were close on both colour and shape at once: Blue Tiara against Tiara moved 9.9 in colour and 1 bit in shape, Blue Face Mask against Face Mask 5.1 and 5 bits, Orange Rowing Man against Rowing Man 11.7 and 1 bit.
The honest read is that colour variants are useful when you need a family that reads as a set, three delivery vans in three colours for a fleet dashboard. They are not useful when you are trying to find one icon, because they pad every result count you see without widening the choice. If a search gave you 40 results, some of those forty are the same drawing in a different paint job.
The category counts under-report, except where it matters
Each icon carries up to three category slots. 92.4 percent of icons have a second one and 48.2 percent have a third, which means any browse view built on the primary category alone shows a fraction of what qualifies.
The gap is large. Objects lists 708 icons as its primary category, but 6,221 icons carry Objects in one of the three slots, 8.8 times more. Entertainment & Games goes from 214 to 932. Symbols from 321 to 1,370. Education from 155 to 644.
It does not rescue every category, though, and it is worth naming the ones it leaves behind. UI & Interface holds 239 as a primary category and 274 across all three slots, a lift of 1.1 times. Flags, Avatar, Emoji & Expressions, Machine and Parts and Zodiac all sit at or near 1.0. Where a category is thin, it is thin in every slot, and no improvement to browsing will change that.
What this library actually is
Put the four measurements together and the shape is unmistakable. Food & Drink is the largest primary category at 1,456 icons. Animals is 1,265, Transportation 1,033, Places & Architecture 943. UI & Interface is 239. Three quarters of every name runs to two words or more, and the single word names include Aardwolf, Affogato and Aeolipile.
Thridy is an illustration library of concrete objects with a very long tail. It is not a UI kit. That is a real and useful thing to be, and it is exactly what makes it work for empty states, onboarding, marketing pages, category art and decks, which is where 3D icons do their best work anyway. It is not what you want as your only source for a settings screen. We would rather write that down than let a headline number imply otherwise.
The ten minute test for any icon library
The count on a library's homepage is a record count. Here is how to get your count instead, and it works on us as well as on everyone else.
Write down the twelve to twenty icons your next screen actually needs, naming each one by the object drawn rather than the action taken. Not "delete" but "trash can". Not "confirm" but "tick". Search each one and record two things: whether a usable icon came back at all, and how many of the results were the same object in another colour. Divide the hits by the length of your list. That fraction is the only coverage number that describes your project, and for most libraries it will look nothing like the number on the homepage.
Then check the depth on the two or three nouns you will need more than one of. If a screen needs six of something and the library has one, you are going to be mixing sources by the end of the week, and mixed sources are how icon sets stop looking like sets. Ten minutes spent counting before you commit is cheaper than finding out on the second sprint.
You can rerun every number in this article yourself. The endpoints are public and need no key.
Free 3D icons for this
Every icon on Thridy is free to download and use. A few that fit this piece:
- Red Rocket 3D icon
- Percentage 3D icon
- Lint Remover 3D icon
- Mango Shaved Ice 3D icon
- Snow Cone Machine 3D icon
- Shaved Ice 3D icon
Browse all 2,600+ free 3D icons or explore them by category.