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User friendly way to see top 100:
https://steemdb.com/witnesses
or
https://steemd.com/witnesses
You can use cli_wallet's list_witnesses command, but that would make no much sense because such list would include also accounts used for miners. A lot of them.

Take a look at #witness-category, feel free to join to #witness channel on steemit.chat, talk to your witnesses. That is a way better method to choose your set of favourite 30 than just looking at a list of nicknames ;-)