You could search for resources for Krita at these addresses, among others:
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Krita Brushes Galore:
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Behind many pictures on Jshinncreative’s DeviantArt page hide bundles for Krita! Just mouse over image by image and pay attention to the description text to recognize the bundles!
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Resources from other software Krita can use:
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Furthermore Krita is able to use some resources of other programs, for example GIMP, MyPaint and Photoshop.
From GIMP you can use the brush-tips (GBR & GIH-Files), the palettes and gradients as well as the pattern files in Krita, but with the patterns you have to be careful because the pattern files from Photoshop use the same file extension but have a different file structure and don’t work.
Here are some good brush sets for GIMP!
More resources for GIMP can be found in huge amounts on DeviantArt and many other places on the internet, just ask Google.
EDIT: I’ve forgotten to add Sam Hutchinsons great Resources.
Also, as of Krita version 5, MyPaint brushes work! You can find some of them for example in the “brushes” directory of your MyPaint installation if you should use the software, but there is also the possibility to download some packs from this Github page.
And on DeviantArt there is a MyPaint community board, on their resources page you can also find some brush sets that are not listed on GitHub, as well as tutorials and other MyPaint materials.
And if you are very bored you can still find some MyPaint resources not listed on the community board on DeviantArt, using their search function (but you will need a lot of patience).
Then most of the Photoshop brush tips work in ABR format too. But the ABR files only work as brush tips in Krita, they can be assigned in the Brush Editor, this is often misunderstood and people look for them among the presets in Krita!
If these ABR’s are ever not accepted by Krita (newer Photoshop CS ABR’s sometimes cause problems), you can try to convert them to the old PS7 format with the program “abrMate”. The converted files will then work in Krita, that works with all ABR’s except the copy protected ABR files (copy protected ones don’t work at least for me). You can find the software “abrMate” either on Achive(dot)org (always works), here is the direct download link.
Or directly from the manufacturer, but that site often has problems.
A top source for very good ABR brush tip packs is Stephanie Shimerdla’s DeviantArt page redheadstock, a stunning collection!
As of Krita 5, Adobe layer styles also work, but not all ASL files (that’s the name of the file extension) seem to work with Krita yet, there are reports of crashes when undoing ASL actions. But maybe this can be fixed until the release version of Krita 5 is released, currently Krita 5 is still in BETA stage!
ABR and ASL files can be found on DeviantArt and many Photoshop sites on the internet. And in this Concept Art Empire article over 70 good ABR brush packs are presented, and the download links are there too.
Michelist
P.S.: I hope this is enough for now? 
P.P.S.: As you can see there are many resources for just about any graphics software on DeviantArt, it’s worth having an account on DA for the resources, their board search has helped me many times, otherwise I don’t like the site as much anymore due to their business practices. Whether you want to use the site, you have to decide for yourself, I just wanted to have pointed out.