the new Salesforce Winter 19 preview instances are live and I have started to dig into the new features. Please add any additional features you identify in the comments:
1. New Winter 19 Logo
2. Chatter
Modified Sort by Box
New button under Poll
3. Density Settings
4. Higher font contrast
5. New Search Box for List Views
6. List Views can now be shared in Lightning with groups of users
7. Copy Paste Images in Email Composer
8. Email Composer quick text available and improved contrast
9. Task Reminder can now be set directly in the Lightning action
11. Dashboard charts can now customise Y-Axis Range
12. Public Groups allow now to invite external People by Email in Lightning
13. Insert Smart Links in Knowledge Articles in Lightning
14. Field Sets are now accessible in Lightning Setup