Sherpa Romeo does a good job aggregating open access policies for a large number of academic journals. This lets me see what OA options (self-archiving of various kinds, full 'diamond' OA with fee, etc.) are available for a given journal. However, it doesn't include information about overall article processing charges (APCs)/OA fees for different routes (e.g., what are the page charges or OA fees for a given journal?)
The Eigenfactor index of Open Access fees has some information, but seems to be out of date. The web page says it's "Powered by Eigenfactor.org and journalprices.com" but going to journalprices.com and clicking "get started" takes you to an old, slightly broken web page; the original Excel sheet can be retrieved from the Wayback machine, but was last modified in 2013.
Academic accelerator has some information: information seems uneven (is it crowd-sourced?), and the site looks sketchy/ad-heavy/ugly.
Obviously keeping such a database up to date would represent a lot of effort, but I'm curious what the best current set of resources is (an ideal version would have open access to the database and would allow easy comparison of journals within a (sub)field ...)
