Here is a list of all documented enum values with links to the documentation:

- r -

RAIL_GROUND_BARREN : rail_map.h
RAIL_GROUND_FENCE_HORIZ1 : rail_map.h
RAIL_GROUND_FENCE_HORIZ2 : rail_map.h
RAIL_GROUND_FENCE_NE : rail_map.h
RAIL_GROUND_FENCE_NESW : rail_map.h
RAIL_GROUND_FENCE_NW : rail_map.h
RAIL_GROUND_FENCE_SE : rail_map.h
RAIL_GROUND_FENCE_SENW : rail_map.h
RAIL_GROUND_FENCE_SW : rail_map.h
RAIL_GROUND_FENCE_VERT1 : rail_map.h
RAIL_GROUND_FENCE_VERT2 : rail_map.h
RAIL_GROUND_GRASS : rail_map.h
RAIL_GROUND_HALF_SNOW : rail_map.h
RAIL_GROUND_ICE_DESERT : rail_map.h
RAIL_GROUND_WATER : rail_map.h
RAIL_TILE_DEPOT : rail_map.h
RAIL_TILE_NORMAL : rail_map.h
RAIL_TILE_SIGNALS : rail_map.h
RAILTYPE_BEGIN : rail_type.h
RAILTYPE_ELECTRIC : rail_type.h
RAILTYPE_END : rail_type.h
RAILTYPE_MAGLEV : rail_type.h
RAILTYPE_MONO : rail_type.h
RAILTYPE_RAIL : rail_type.h
RAILVEH_MULTIHEAD : engine_type.h
RAILVEH_SINGLEHEAD : engine_type.h
RAILVEH_WAGON : engine_type.h
REF_CARGO_PACKET : saveload.h
REF_ENGINE_RENEWS : saveload.h
REF_LINK_GRAPH : saveload.h
REF_LINK_GRAPH_JOB : saveload.h
REF_ORDERLIST : saveload.h
REF_ROADSTOPS : saveload.h
REF_STATION : saveload.h
REF_STORAGE : saveload.h
REF_TOWN : saveload.h
REF_VEHICLE : saveload.h
REF_VEHICLE_OLD : saveload.h
Reserved : newgrf_config.h
Reversed : train.h
Reversing : train.h
RFO_FLAT_LEFT : rail.h
RFO_FLAT_LOWER : rail.h
RFO_FLAT_RIGHT : rail.h
RFO_FLAT_UPPER : rail.h
RFO_FLAT_X_NW : rail.h
RFO_FLAT_X_SE : rail.h
RFO_FLAT_Y_NE : rail.h
RFO_FLAT_Y_SW : rail.h
RFO_SLOPE_NE_NW : rail.h
RFO_SLOPE_NE_SE : rail.h
RFO_SLOPE_NW_NE : rail.h
RFO_SLOPE_NW_SW : rail.h
RFO_SLOPE_SE_NE : rail.h
RFO_SLOPE_SE_SW : rail.h
RFO_SLOPE_SW_NW : rail.h
RFO_SLOPE_SW_SE : rail.h
RM_ADVANCED : settingentry_gui.h
RM_ALL : settingentry_gui.h
RM_BASIC : settingentry_gui.h
RM_CHANGED_AGAINST_DEFAULT : settingentry_gui.h
RM_CHANGED_AGAINST_NEW : settingentry_gui.h
RM_END : settingentry_gui.h
ROAD_ALL : road_type.h
ROAD_E : road_type.h
ROAD_END : road_type.h
ROAD_N : road_type.h
ROAD_NE : road_type.h
ROAD_NONE : road_type.h
ROAD_NW : road_type.h
ROAD_S : road_type.h
ROAD_SE : road_type.h
ROAD_SW : road_type.h
ROAD_TILE_CROSSING : road_map.h
ROAD_TILE_DEPOT : road_map.h
ROAD_TILE_NORMAL : road_map.h
ROAD_W : road_type.h
ROAD_X : road_type.h
ROAD_Y : road_type.h
ROADSIDE_BARREN : road_map.h
ROADSIDE_GRASS : road_map.h
ROADSIDE_GRASS_ROAD_WORKS : road_map.h
ROADSIDE_PAVED : road_map.h
ROADSIDE_PAVED_ROAD_WORKS : road_map.h
ROADSIDE_STREET_LIGHTS : road_map.h
ROADSIDE_TREES : road_map.h
ROADSTOP_CLASS_BEGIN : newgrf_roadstop.h
ROADSTOP_CLASS_DFLT : newgrf_roadstop.h
ROADSTOP_CLASS_MAX : newgrf_roadstop.h
ROADSTOP_CLASS_WAYP : newgrf_roadstop.h
ROADSTOPTYPE_ALL : newgrf_roadstop.h
ROADSTOPTYPE_FREIGHT : newgrf_roadstop.h
ROADSTOPTYPE_PASSENGER : newgrf_roadstop.h
ROADTYPE_BEGIN : road_type.h
ROADTYPE_END : road_type.h
ROADTYPE_ROAD : road_type.h
ROADTYPE_TRAM : road_type.h
ROTSG_BRIDGE : road.h
ROTSG_CATENARY_BACK : road.h
ROTSG_CATENARY_FRONT : road.h
ROTSG_CURSORS : road.h
ROTSG_DEPOT : road.h
ROTSG_GROUND : road.h
ROTSG_ONEWAY : road.h
ROTSG_OVERLAY : road.h
ROTSG_reserved2 : road.h
ROTSG_reserved3 : road.h
ROTSG_ROADSTOP : road.h
ROTSG_TUNNEL : road.h
RSV_BAY_NE : newgrf_roadstop.h
RSV_BAY_NW : newgrf_roadstop.h
RSV_BAY_SE : newgrf_roadstop.h
RSV_BAY_SW : newgrf_roadstop.h
RSV_DRIVE_THROUGH_X : newgrf_roadstop.h
RSV_DRIVE_THROUGH_Y : newgrf_roadstop.h
RTBO_SLOPE : rail.h
RTBO_X : rail.h
RTBO_Y : rail.h
RTO_CROSSING_XY : rail.h
RTO_E : rail.h
RTO_JUNCTION_NE : rail.h
RTO_JUNCTION_NSEW : rail.h
RTO_JUNCTION_NW : rail.h
RTO_JUNCTION_SE : rail.h
RTO_JUNCTION_SW : rail.h
RTO_N : rail.h
RTO_S : rail.h
RTO_SLOPE_NE : rail.h
RTO_SLOPE_NW : rail.h
RTO_SLOPE_SE : rail.h
RTO_SLOPE_SW : rail.h
RTO_W : rail.h
RTO_X : rail.h
RTO_Y : rail.h
RTSG_BRIDGE : rail.h
RTSG_CROSSING : rail.h
RTSG_CURSORS : rail.h
RTSG_DEPOT : rail.h
RTSG_FENCES : rail.h
RTSG_GROUND : rail.h
RTSG_GROUND_COMPLETE : rail.h
RTSG_OVERLAY : rail.h
RTSG_PYLONS : rail.h
RTSG_SIGNALS : rail.h
RTSG_TUNNEL : rail.h
RTSG_TUNNEL_PORTAL : rail.h
RTSG_WIRES : rail.h
RTT_ROAD : road_type.h
RTT_TRAM : road_type.h
RTTB_ROAD : road_type.h
RTTB_TRAM : road_type.h
RVS_DRIVE_SIDE : roadveh.h
RVS_ENTERED_STOP : roadveh.h
RVS_IN_DT_ROAD_STOP : roadveh.h
RVS_IN_ROAD_STOP : roadveh.h
RVS_USING_SECOND_BAY : roadveh.h
RVSB_DRIVE_SIDE : roadveh.h
RVSB_IN_DEPOT : roadveh.h
RVSB_IN_DT_ROAD_STOP : roadveh.h
RVSB_IN_ROAD_STOP : roadveh.h
RVSB_ROAD_STOP_TRACKDIR_MASK : roadveh.h
RVSB_TRACKDIR_MASK : roadveh.h
RVSB_WORMHOLE : roadveh.h
RWV_HIDE_BEVEL : widget_type.h
RWV_SHOW_BEVEL : widget_type.h