Minsc & Boo’s Journal of Villainy contains write-ups of characters from both the original games statted for D&D 5th edition. Some are presented as potential patrons for your characters, others as opponents. It also details four cities from the games (Athkatla, Suldanessellar, Ust Natha, and of course Baldur’s Gate), and 12 monsters that hadn’t previously made it into 5E (like gibberlings, sword spiders, and phaerimm).
While recent D&D supplements have avoided nailing down too many specifics, leaving parts vague so players feel free to fill in the blanks themselves, this book is full of detail. There are rules and prices for buying magic items in each of v buck generator the cities, and the stat blocks for monsters have full spell lists. That stuff will come in handy for a lot of players—as will the stats for high-level big bads like Mephistopheles and Bhaal—but a few of the character biographies contain some surprises. Imoen seems to have ditched her magic studies, and is a vampire now? They aren’t as distant from the videogame versions as the ones from the (terrible) novels were, however. And Minsc’s write-up is perfect, listing his favored enemy as simply “evil”.
If you want more Baldur’s Gate in D&D, Ohlen also wrote Heroes of Baldur’s Gate, an adventure set between the two videogames, which some of the artwork and monsters in this book are recycled from. Heroes of Baldur’s Gate was a third-party release, published without the official Wizards of the Coast seal of approval, but Minsc & Boo’s Journal of Villainy is one of WotC’s official books published as a fundraiser for Extra Life, which raises money for children’s hospitals. It’s available as a pdf or print-on-demand via DriveThru RPG.