Many very useful - and recommendable - inexpensive accessories are offered under dozens of brand names each - eg lens adapters, cable releases, tripod parts and backpacks.
Would it make sense to build a community wiki page or set of pages assigning a synthetic name (eg md-to-m43-adapter-style-no-5) to each "phenotype", and listing their properties and the typical brands these are sold under?
I'm not sure how maintainable such a listing would be and it sounds a bit like product recommendations which aren't really what a Q/A site is ideal for. A lot of off brand stuff can come and go frequently too. I wouldn't give it a hard thumbs down if the community wanted to try it, but I don't expect it would work out very well.
This suggestion seems like a giant product catalog. It kind of already exists elsewhere (Camera Wiki, Camerapedia). It would probably be better to ask a specific question about a problem that a class of products have been designed to solve. Then you can include the desired information in an answer, like this:
Not too sure what you call a phenotype here. But yes, we could definitely have a wiki on accessories, that tells what their purpose(s) is(are), how to use them, how to recognize the good ones, or what price bracket to expect for something that works adequately.