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;"