Greasy Fork is available in English.
Add buttons (past 1/2/3 days, weeks, PDF search etc.) for Google search page
< Σχολιασμός για τον κώδικα Google Search Extra Buttons
Check, please, this instruction https://greasyfork.org/en/scripts/7543-google-search-extra-buttons/discussions/141609 (Aug 22 2022) for installation in Opera GX. (Tampermonkey should not works as in Opera.)
Unfortunately, doesn't work with Opera GX.