The first 6 or so are I-frame based codecs which take up more storage than LongGOP codecs but are more efficient and hold up to multi-generational loss a lot better. DNx flavors are Avid native codecs developed by Avid whereas ProRes is also native, but developed by Apple and can be decoded on Mac and PC but only encoded on Mac.
The multiple flavors of each are encoding data rates and different in bit depth. Anything with an x after it is 10 bit. Naming changes with DNxHR where the different levels are also different data rates and bit depth.
It is a balance of choosing based on storage, source codec, desired bit depth, detail preservation (based on the type of content), and your workflow offline/online, online online, etc.
DNxHD is for HD formats 720, 1080 and 16:9 aspect ratio only, whereas DNxHD is scalable at most any resolution and aspect ratio. If you make an HD project, you can’t select DNxHR. More info on DNxHD from the original whitepaper 10 or so years ago:
https://www.avid.com/static/resources/US/documents/dnxhd.pdf
Michael