Control Googlebot crawl rate
You can now control how frequently Googlebot crawls your site over the next 90 days. Webmasters can ask Googlebot to slow down or speed up for the next 90 days. Your choice may affect your total bandwidth usage but the tradeoff is possibly more frequent visits from Google’s discovery and indexing tools.
Enhanced image search
I’m a big fan of Google Webmaster Tools to maintain a better relationship with what can be my biggest source of referrals. The new tweaks from Google allow Google to learn more about my site and possibly send a few more referrals my way using current and experimental methods. Not everyone uses Google’s Webmaster Tools, so I feel like I have a bit of an edge, however artificial that hope may be.