@VaylLarkinPoet My first stop when I need articles is the BASE search engine, which favors open access articles (you can filter for that in the advanced search). I did a quick search for "trans healthcare" limited to open access and public domain and got 1.318 hits. With alternate search terms and such, they might be able to get more.

There's also the KVK - I'm German, so bear with me that I have a big focus on German/European search engines and databases. It's a catalogue that indexes international databases. I find it rather tedious to use, especially since its filter options are lacking, but it's pretty good if you need a starting point for your research. My quick search showed a fair amount of open access articles (in English) in the German library networks.

BASE: https://www.base-search.net/
KVK: https://kvk.bibliothek.kit.edu

Also, if they have access to an academic library, they often license additional databases.

Lastly, you can often ask the researchers themselves for a copy of an article, but I personally consider that a last resort. It might also not be legal in all countries, I'm not well-versed in international law around that.

(Source for all this: I'm a specialist for media and information sciences. Which is a fancy way to say "library assistant", but we are trained extensively in research, specifically literature research.)

@VaylLarkinPoet If you find an article and cannot access it, emailing the corresponding author usually leads to someone eager to share their research

Libgen and SciHub also exist, but should be avoided because they are illegal and thus bad and wrong and evil, knowledge likes being behind paywalls!