Graeber is basically "must read" as far as i'm concerned; for anarchists and would-be anarchists, i'd say a comparable figure is Peter Gelderloos.
on the more obscure end, i've found the bibliographies of Walter Rodney and Amílcar Cabral to be quite good; perhaps not broadly applicable to modern socialism, but both definitely profile worthwhile international and historical perspectives (Rodney with Caribbean, Guyanese, and Black socialism; Cabral with the liberation war fought in Guinea-Bissau against the colonial Portuguese) that shouldn't be forgotten. since they're lesser-known you probably can't find their stuff in print, but most of their works can definitely be found on libgen