“Unknown (Family)” projects

Yes.

But if you use some of the links provided in a project description, you can filter out the observations already identified. (I also included reviewed=false in the links, to help you skip some observations).

For instance, see this project, its statistics (353 observations, 200 already identified):

https://www.inaturalist.org/projects/unknown-caesalpinioideae

and the links in its description:

Subfamily Caesalpinioideae observations without id. (or high rank id.).

Identify observations without id.

Identify observations with high rank id.

Parent projects: Fabaceae, Fabales, Magnoliopsida, Tracheophyta, Plantae, Life.