I used to use "vector" tag to find images with transparent backgrounds.

Yet I find that half of them are not extracted (ie. 64799), and some pictures with transparent background are not necessary vectors (ie. 64713)....

Any suggestions?

We don't have a tag for that.

The vector tag is simply for images that have been vectored even if they have not been extracted out. Another tag you may want to use is "Extraction" which are images that have been extracted from the background.

You can also use render, but there's only 5 results so extraction is a better term, well... at least for Moe.

I would say transparent is better than extraction.
Transparency doesn't really mean the entire image is extracted.

It is but as of now we don't have any tags for it though...

Currently i don't see any issues to go retag images with transparency, and since the tag "extraction" would most already mean they are extracted and a transparent background.

2 birds with 1 stone :)

Wouldn't "transparent_png" or just "transparent" be a better tag choice? Not all transparent pngs are extractions and it's incorrect to label them all as such.

All of the "extraction" tags are correct.

Extraction are just extracted images, nothing else. Not transparent, not vectored. Some of them have the "vector" tags because they really are vectored images, either extracted or left like that.

Also I don't see anybody using that tag without previously seeing a post with using that tag because it's little intuitive.