Nice HTML site and download free html::
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https://www.free-css.com/
https://onepagelove.com/
https://w3layouts.com/
Diferent Hover Animation, slider Related
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https://www.cssscript.com/
https://www.jqueryscript.net/
codrops tympanus
https://codepen.io/
https://codepen.io/vii120/pen/BarXpGX
https://www.jqueryscript.net/tags.php?/Thumbnail/
Flex related:
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https://css-tricks.com/using-flexbox/
Animation Tabs related:
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https://www.sliderrevolution.com/resources/css-tabs/
Swipper Slider:
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https://swiperjs.com/demos
Modal Related
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https://codepen.io/sachinchoolur/pen/yLbzGQG
https://codepen.io/Jeevithapriya/full/VwYdPjz