Below query can help you to find which field contains the largest value of autoload field in options table.
SELECT option_name, LENGTH(option_value), autoload FROM wp_options WHERE autoload = 'yes' ORDER BY `LENGTH(option_value)` DESC
NOTE: change your table prefix as per your site.
WP-CLI:
wp db query "SELECT option_name, LENGTH(option_value), autoload FROM wp_options WHERE autoload = 'yes' ORDER BY LENGTH(option_value) DESC;"