With hundreds of thousands of active installations Meta Box is one of the premier methods of managing Custom Fields on your WordPress website.

Meta Box takes a code-focused approach to custom fields, and developers have latched on because of its unique approach to implementing meta boxes.
Meta Box and SearchWP

With SearchWP’s Meta Box Integration, you’ll be able to easily add your Meta Box fields to your search engines, they’re organized by the Meta Boxes you set up:
Animated GIF adding Meta Box fields to a SearchWP engine

Easily add Meta Box fields to SearchWP engines

Further, Meta Box Integration also makes your MB Custom Table content searchable as well!