Find the raw list here:
https://raw.githubusercontent.com/bhadaway/list-of-article-words/main/list.txt
The AP/APA style guide is very good concerning title case:
https://apastyle.apa.org/style-grammar-guidelines/capitalization/title-case
However, my list is slightly more opinionated. Also, the following words are not included in the list, but I sometimes struggle with them because they can often look goofy both in capitalized or non-capitalized form, depending on the context:
are
be
do
has
into
that
then
this
was
when