The BCN website has articles on news, events, listings of bi+ groups and other information. You can also subscribe to their bi-monthly magazine for even more bi articles.
Bi's of Colour is a group for bisexual people of colour. They meet once a year at BiCon as well as having an online presence on Tumblr. They have also published a Bi's of Colour Survey Report available here.
The Bisexual Index is a great website with lots of information such as Bisexuality FAQs, Coming Out and Am I Bisexual?
The Bisexuality Report was published in 2012 exploring biphobia, health and intersectionality.
The Equality Network in Scotland published Complicated? in 2015. This study looked specifically at bisexual peoples experiences of accessing services such as health care and LGBT organisations. They also published the Roadmap to Bisexual Inclusion in 2018.
Stonewall is the UK's biggest LGBT charity. They have a range of bi+ specific resources and published research. In 2017 they launched their "Bi Allies" training.