I hoped to find an addon that doesn't only show me which materials I need to craft an item, but also the other way round: That I can see in the tooltip of a crafting material, which items I can craft with them, and which profession (and profession level) is needed. That would make it much easier to decide if - for example - a cooking mat is further needed or can be auctioned/vendored.

Got a version that works with classic too:

Run the chat command /cia rti to enable seeing what the reagents can be made into

CraftInfoAnywhere-1.10-2-g9245dd4.zip

Put a version together, and it results in a really long tooltip for some items:

The cooking reagents lists aren't so long though:

Try this build (retail only at the moment) and let me know how it goes
CraftInfoAnywhere-1.10-1-g5a9945b.zip

I'm impressed. A solution for my request on the same day. Thank you very much. Seems to work in Classic (Era), will test it further on when skilling cooking and enchanting... :-)