I find a new free clipart site (ClipartMax) which focuses on transparent clipart images collection with png format. All png clipart pictures with transparent background are high quality, easy to use. Just to search and unlimited download for free.
This is the first time I found this clip art resource site. I tried to search some clip art data inside, I am very happy, all the clip art is transparent and high quality.
For example, i search "fish clipart" - https://www.clipartmax.com/so/fish-clipart/
For example, i search "flower clipart" - https://www.clipartmax.com/so/free-clip-art-flowers/