Niels Dewitte also has some textures on his homepage:
It’ll be hard to find 1024² textures throughout as it is (has been) not common to use textures large than 512² for simple shapes. Most of the time you can even get away with using 128² or 256², depending on the size of the effect. If your sprite is not large than 512px on screen, there is no benefit of having a 1024² texture.
You can always manually scale those up in an image software and slightly blur them to get rid of artifacts.
Or you create your own, e.g. with this tool:
https://mebiusbox.github.io/contents/EffectTextureMaker/
On a side note: Having a massive library can be nice, but it’s quite likely you’ll be using the same shape textures over and over anyway. At least for 90% of your fx. This is all the more true for noise textures. Just having aving about 5-10 high quality noise textures will set you up for life 