If someone had an idea for a coin with a purpose, where would be the best place to get help? If it's a good idea, that's just the beginning. Getting it done before someone else does it would be nice. That is assuming it hasn't been done. Who can keep up these days?
If you are looking for a developer to materialize your idea, the best place to look is on Github, on this forum, and on Fiverr, I don't like Linkedin, although you can see projects posting their team Linkedin profile, they do not have a KYC there you can post any credentials that you can think of.
On Github : You can check the repository of their previous works
On Fiverr: of course you can see their feedback and sample of their works
Bitcointalk You can easily tell how good they are by the way they post and communicate.