List of genera featuring rhizobia and agrobacteria, and links to the List of Prokaryotic names with Standing in Nomenclature (LPSN) at bacterio.net.
Taxa with rhizobia:
Alphaproteobacteria
Phyllobacteriaceae
Brucellaceae
Methylobacteriaceae
Bradyrhizobiaceae
Xanthobacteraceae
Hyphomicrobiaceae
Betaproteobacteria
Burkholderiaceae
Taxa with agrobacteria:
Alphaproteobacteria
Rhizobiaceae
(mostly R. rhizogenes and R. tumorigenes)
(only A. vitis)
Below is a (possibly) more up-to-date list of species of rhizobia and agrobacteria, with additional information such as the reference genome sequence of the (type) strain and corresponding metadata: