Brian wants to know if there's an easy way to search for things on his Mac. Leo says that CMD + spacebar will bring up spotlight search. He can just start typing and he'll find what he needs right away.
Brian also wants a central depository like Evernote for his desktop where he can tag things. There's a ton of choices including Google Keep, Simple Note, Bear, and Quip. Scrivener is a great option for researchers. Leo also says there's recipes on If This Then That (ifttt.com) that could work. Brian would also like a voice command option, and be able to save his data locally.
For a self-hosted option, Synology has an Evernote clone for their NAS. Turtl would work as well. The Chatroom says that StandardNotes.org is a good open source option that syncs, encrypts and backs up. It's cross-platform, too.