I'm working with a Magento 2 stack, I'm reusing some of my Magento 1 OpCache configuration. I've already learned that now we need to enable comments but I'm pretty sure that other values can be improved, so here is my current configuration:
[opcache]
opcache.enable=1
opcache.enable_cli=0
opcache.memory_consumption=256
opcache.interned_strings_buffer=12
opcache.max_accelerated_files=65406 // thanks Mage2.Pro!
;opcache.max_wasted_percentage=5
;opcache.use_cwd=1
opcache.validate_timestamps=0
;opcache.revalidate_freq=2
;opcache.revalidate_path=0
;opcache.save_comments=0
;opcache.load_comments=0
opcache.fast_shutdown=1
opcache.enable_file_override=1
;opcache.optimization_level=0xffffffff
;opcache.inherited_hack=1
;opcache.dups_fix=0
;opcache.blacklist_filename=
;opcache.max_file_size=0
;opcache.consistency_checks=0
;opcache.force_restart_timeout=180
opcache.error_log=/var/log/php5/php5-opcache.error.log
opcache.log_verbosity_level=3
;opcache.preferred_memory_model=
;opcache.protect_memory=0
NOTE: I will edit the configuration block in the question (while opened) with all good answers in order to make it useful for everyone, and avoid repeated suggestions too, if there is any problem about that or represents a violation to the site rules, just let me know.