For anyone who hasn't seen them before, Hidden Search Operators are handy tricks you can use when you're either searching or filtering AO3.
summary: string is a generic way of explaining that you can search AO3 for a specific word that appears in a summary. You can do this from the search bar in the header, from the Any Field box at the top of the Advanced Search form, or from the Search Within Results box at the bottom of the filter menu.
Examples:
summary: Bruce
summary: "Bruce Banner"
summary: Bruce OR summary: Banner OR summary: Hulk
You need to put quotation marks around your search term if it is more than one word. The quotes make sure that the site searches for those two words together.
The other two operators listed work best in the Search Within Results box.
expected_number_of_chapters: 1 will return results where every fic has only 1 chapter currently posted.
You can use expected_number_of_chapters: -1 if you want results where every fic has more than 1 chapter currently posted.
otp:true will return results where there is only 1 relationship tag on the fic. If you want results where there are 2+ relationship tags (and no fics with only 1 relationship tag) then you can use otp:false
I mean, there is a secret way to filter for primary ship if that's what you're looking for?
You need to install a userscript in your browser, so if you're a mobile user you'll want to use Firefox instead of Chrome (Chrome doesn't allow users to install scripts in the mobile version of the app).
The script is called AO3 Only Show Primary Pairing and what it does is filter out fics that don't have your indicated ship as the first (or only) relationship tagged.
If you've never installed a userscript before, click or tap on the ? in green next to where it says Install this script. That'll take you through the process of doing it for the first time.
The code itself is commented, so you should be able to to just drop your info into it. They give you an example ship in the relationship field and you can add in characters as well (or instead) if you prefer.
You can also adjust how many tags it looks at. Default, it just looks at the first 1 but if you want it to look at the first 2 or 3, you can just adjust the numbers.
Edit: also I just realized this is a branch of this post that doesn't have my correction. To remove oneshots, the syntax is actually
-expected_number_of_chapters: 1
