Font Book crashing on startup

The good news is that a new account working properly means the issue is somewhere in your normal account, and not anything that would require reinstalling the OS.

Unless you're a developer and need to test how your apps will look when pointed to the hidden system San Francisco font, I would entirely remove the non-hidden versions. It's just another sans serif font that's only slightly different from Arial, Helvetica, Tahoma and others.

To reset Font Book entirely takes a few steps, done in a particular order. I'm going to be lazy and copy/paste from my article. :-)

1) Quit Font Book. Open the Preferences folder in your user account and put the following two files in the trash.

com.apple.FontBook.plist

com.apple.FontRegistry.user.plist

The file com.apple.FontBook.plist keeps track of Font Book's general preferences and activated fonts, whether as a standard or library collection. com.apple.FontRegistry.user.plist keeps track of deactivated fonts. Both may not be present. Delete what's there.

2) Open Terminal and enter this command:

sudo atsutil databases -remove

Enter your administrator password when prompted. This removes all font cache files maintained by macOS.

3) Restart your Mac and immediately hold down the Shift key to boot into Safe Mode. Keep holding the Shift key until macOS asks you to log in to your user account (you will get this screen on a Safe Mode boot even if your Mac is set to automatically log in). Let the Mac finish booting to the desktop and then restart normally. This will clear the remainder of Font Book's database and the cache files for the user account you logged into in Safe Mode.

These combined steps put Font Book's settings, caches and other hidden data back to square one. The next time it's launched, it will rebuild all new data.

If after this the problem still remains, you may:

1. Have third party fonts in your user account folder, or the root /Library/Fonts/ folder that are causing Font Book to choke.
2. One or more font collections may be damaged. Font Book will crash pretty much immediately if they are.