Back in the day we created the campaign extension to make it easy for people to upload their photos of monument for Wiki Loves Monuments. The only thing a user needed to enter was the id of the monument. For example https://commons.wikimedia.org/wiki/Campaign:wlm-nl is the campaign for the Netherlands with the configuration at https://commons.wikimedia.org/w/index.php?title=Campaign:wlm-nl&action=edit . The latest upload is https://commons.wikimedia.org/wiki/File:Gendringen_Anholtseweg_78_01_(1).jpg where the user added "523699". User retrieve the number from the list ( like https://nl.wikipedia.org/wiki/Lijst_van_rijksmonumenten_in_Gendringen) or from an app.
This workflow seems to work, but we also want to add depicts -> Qid of the monument without bothering the user too much. We know the id, the user just entered it and we know that Rijksmonumenten use property Rijksmonument ID (P359) so we can ask the search engine for the item: https://www.wikidata.org/wiki/Special:Search?search=haswbstatement%3AP359%3D523699&fulltext=Search+for+%2719264%27&fulltext=Search&ns0=1&ns120=1 which yields https://www.wikidata.org/wiki/Q17601397 (of course you'll hit the API version of the search engine). You can now pre-fil the "add data" step with depicts (P180) -> Q17601397.
You have to track what property to look up in the configuration (P359), or maybe better just track the lookup string "haswbstatement:P359=$1" and what property to add based on that string. That gives more flexibility so we might be able to use it for more creative things.