Most of my experiences with DMsGuild to date have been with adventures and encounters, today I'll be going a slightly different route looking at a new and unique subclass of the Druid designed specifically for urban adventure.
The Circle Of Balance is by author Beth Ball of Grove Guardian Press (the design team behind D&D Duets) and is a great example of the kind of content that can really add new content to a D&D 5e game. In brief the core notion of The Circle Of Balance is that civilization is a part of nature, and as protectors and/or shepherds the city can and is part of a Druid's responsibilities.
The subclass itself seems extremely well balanced adding some martial strengths at lower levels, which make for a good trade off for some of a Druid's basic spells which may be of dubious use in a city. In addition the Circle spells that have been added give the Druid some additional typically non-druidic utility powers that play off the people and materials that make up a typical urban environment in a fantasy world. For any fans of the comic The Authority (or later runs of Stormwatch) this subclass and its Circle spells are a great starting point to make a character similar to Jack Hawksmoor (minus the suit and tie). In addition to the mechanical additions that serve balancing a Druid in a new environment there are a number of features that really tie to the theme of operating in the packed terrain of the city. "Wildly Compact" which allows more compact versions of Wild Shape animal forms to be adopted.
In addition to the subclass rules themselves the supplement also adds rules for 2 new creatures; The Fey Pug and The Jewel Fox as well as formatting The Fey Pug as a D&D Sidekick. I know in my home game this has the potential to be right up my daughter's alley.
Overall Circle Of Balance is a unique and worthwhile addition to the existing player options in D&D and is well balanced enough to drop into an existing campaign without upsetting the power balance of existing classes.
I strongly recommend Circle Of Balance to both players looking for a new option for their Waterdeep campaigns as well as DMs potentially looking for a new template for sage NPCs in an urban setting.
Circle Of Balance is currently available from DMsGuild at https://www.dmsguild.com/product/294719/Circle-of-Balance-druid-subclass?term=circle+of+bal for $1