From the csgo_english.txt language file:
// nice map names
"SFUI_Map_overwatch" "Overwatch"
"SFUI_Map_cs_assault" "Assault"
"SFUI_Map_cs_italy" "Italy"
"SFUI_Map_cs_militia" "Militia"
"SFUI_Map_cs_office" "Office"
"SFUI_Map_de_aztec" "Aztec"
"SFUI_Map_de_dust" "Dust"
"SFUI_Map_de_dust2" "Dust II"
"SFUI_Map_de_mirage" "Mirage"
"SFUI_Map_de_overpass" "Overpass"
"SFUI_Map_de_cbble" "Cobblestone"
"SFUI_Map_de_train" "Train"
"SFUI_Map_de_inferno" "Inferno"
"SFUI_Map_de_nuke" "Nuke"
"SFUI_Map_de_shorttrain" "Shorttrain"
"SFUI_Map_de_shortdust" "Shortdust"
"SFUI_Map_de_vertigo" "Vertigo"
"SFUI_Map_de_balkan" "Balkan"
"SFUI_Map_random" "Random"
"SFUI_Map_ar_baggage" "Baggage"
"SFUI_Map_ar_monastery" "Monastery"
"SFUI_Map_ar_shoots" "Shoots"
"SFUI_Map_de_embassy" "Embassy"
"SFUI_Map_de_bank" "Bank"
"SFUI_Map_de_lake" "Lake"
"SFUI_Map_de_depot" "Depot"
"SFUI_Map_de_safehouse" "Safehouse"
"SFUI_Map_de_sugarcane" "Sugarcane"
"SFUI_Map_de_stmarc" "St. Marc"
"SFUI_Map_training1" "Weapons Course"
"SFUI_Map_cs_museum" "Museum"
"SFUI_Map_cs_thunder" "Thunder"
"SFUI_Map_de_favela" "Favela"
"SFUI_Map_cs_downtown" "Downtown"
"SFUI_Map_de_seaside" "Seaside"
"SFUI_Map_de_library" "Library"
"SFUI_Map_cs_motel" "Motel"
"SFUI_Map_de_cache" "Cache"
"SFUI_Map_de_ali" "Ali"
"SFUI_Map_de_ruins" "Ruins"
"SFUI_Map_de_chinatown" "Chinatown"
"SFUI_Map_de_gwalior" "Gwalior"
"SFUI_Map_cs_agency" "Agency"
"SFUI_Map_cs_siege" "Siege"
"SFUI_Map_de_castle" "Castle"
"SFUI_Map_de_overgrown" "Overgrown"
"SFUI_Map_de_blackgold" "Black Gold"
"SFUI_Map_cs_rush" "Rush"
"SFUI_Map_de_mist" "Mist"
"SFUI_Map_cs_insertion" "Insertion"
"SFUI_Map_cs_workout" "Workout"
"SFUI_Map_cs_backalley" "Back Alley"
"SFUI_Map_de_marquis" "Marquis"
"SFUI_Map_de_facade" "Facade"
"SFUI_Map_de_season" "Season"
"SFUI_Map_de_bazaar" "Bazaar"
"SFUI_Map_de_rails" "Rails"
"SFUI_Map_de_zoo" "Zoo"
"SFUI_Map_de_log" "Log"
"SFUI_Map_de_resort" "Resort"
"SFUI_Map_gd_bank" "Bank"
"SFUI_Map_gd_lake" "Lake"
"SFUI_Map_gd_cbble" "Cobblestone"
"SFUI_Map_gd_crashsite" "Crashsite"