Well you could have a look at the Bitcoin Core developers.  Gavin Andresen would be another relevant figure.

If you're looking for particularly early users, you could have a look at satoshi's post history and the other people that posted - people like Hal Finney, theymos, Gavin Andresen and Sirius were around at the time.

Here is a list of 100 relevant figures.

This is really a complete list of very famous people and a voice in the cryptocurrency market. They are very successful in this market although each one develops in different directions. Very thanks for your sharing on this list.