SELECT DISTINCT p.proname AS function_name, t.typname AS return_type
FROM pg_catalog.pg_extension AS e
    INNER JOIN pg_catalog.pg_depend AS d ON (d.refobjid = e.oid)
    INNER JOIN pg_catalog.pg_proc AS p ON (p.oid = d.objid)
    INNER JOIN pg_type AS t ON (t.oid = p.prorettype)
WHERE e.extname = 'postgis' AND d.deptype = 'e' AND (t.typname = 'geometry' OR t.typname = 'geography')
ORDER BY 1, 2;
+----------------------------------+---------------+
| function_name                    | return_type   |
|----------------------------------+---------------|
| _st_concavehull                  | geometry      |
| _st_expand                       | geography     |
| _st_geomfromgml                  | geometry      |
| _st_longestline                  | geometry      |
| _st_pointoutside                 | geography     |
| _st_voronoi                      | geometry      |
| geography                        | geography     |
| geography_in                     | geography     |
| geography_recv                   | geography     |
| geometry                         | geometry      |
| geometry_in                      | geometry      |
| geometry_recv                    | geometry      |
| geomfromewkb                     | geometry      |
| geomfromewkt                     | geometry      |
| pgis_geometry_collect_finalfn    | geometry      |
| pgis_geometry_makeline_finalfn   | geometry      |
| pgis_geometry_polygonize_finalfn | geometry      |
| pgis_geometry_union_finalfn      | geometry      |
| postgis_addbbox                  | geometry      |
| postgis_dropbbox                 | geometry      |
| postgis_geos_noop                | geometry      |
| postgis_noop                     | geometry      |
| postgis_transform_geometry       | geometry      |
| st_3dclosestpoint                | geometry      |
| st_3dlineinterpolatepoint        | geometry      |
| st_3dlongestline                 | geometry      |
| st_3dshortestline                | geometry      |
| st_addmeasure                    | geometry      |
| st_addpoint                      | geometry      |
| st_affine                        | geometry      |
| st_asmvtgeom                     | geometry      |
| st_bdmpolyfromtext               | geometry      |
| st_bdpolyfromtext                | geometry      |
| st_boundary                      | geometry      |
| st_boundingdiagonal              | geometry      |
| st_buffer                        | geography     |
| st_buffer                        | geometry      |
| st_buildarea                     | geometry      |
| st_centroid                      | geography     |
| st_centroid                      | geometry      |
| st_chaikinsmoothing              | geometry      |
| st_cleangeometry                 | geometry      |
| st_clipbybox2d                   | geometry      |
| st_closestpoint                  | geometry      |
| st_collect                       | geometry      |
| st_collectionextract             | geometry      |
| st_collectionhomogenize          | geometry      |
| st_concavehull                   | geometry      |
| st_convexhull                    | geometry      |
| st_curvetoline                   | geometry      |
| st_delaunaytriangles             | geometry      |
| st_difference                    | geometry      |
| st_endpoint                      | geometry      |
| st_envelope                      | geometry      |
| st_expand                        | geometry      |
| st_exteriorring                  | geometry      |
| st_filterbym                     | geometry      |
| st_flipcoordinates               | geometry      |
| st_force2d                       | geometry      |
| st_force3d                       | geometry      |
| st_force3dm                      | geometry      |
| st_force3dz                      | geometry      |
| st_force4d                       | geometry      |
| st_forcecollection               | geometry      |
| st_forcecurve                    | geometry      |
| st_forcepolygonccw               | geometry      |
| st_forcepolygoncw                | geometry      |
| st_forcerhr                      | geometry      |
| st_forcesfs                      | geometry      |
| st_generatepoints                | geometry      |
| st_geogfromtext                  | geography     |
| st_geogfromwkb                   | geography     |
| st_geographyfromtext             | geography     |
| st_geomcollfromtext              | geometry      |
| st_geomcollfromwkb               | geometry      |
| st_geometricmedian               | geometry      |
| st_geometryfromtext              | geometry      |
| st_geometryn                     | geometry      |
| st_geomfromewkb                  | geometry      |
| st_geomfromewkt                  | geometry      |
| st_geomfromgeohash               | geometry      |
| st_geomfromgeojson               | geometry      |
| st_geomfromgml                   | geometry      |
| st_geomfromkml                   | geometry      |
| st_geomfromtext                  | geometry      |
| st_geomfromtwkb                  | geometry      |
| st_geomfromwkb                   | geometry      |
| st_gmltosql                      | geometry      |
| st_interiorringn                 | geometry      |
| st_intersection                  | geography     |
| st_intersection                  | geometry      |
| st_linefromencodedpolyline       | geometry      |
| st_linefrommultipoint            | geometry      |
| st_linefromtext                  | geometry      |
| st_linefromwkb                   | geometry      |
| st_lineinterpolatepoint          | geometry      |
| st_lineinterpolatepoints         | geometry      |
| st_linemerge                     | geometry      |
| st_linestringfromwkb             | geometry      |
| st_linesubstring                 | geometry      |
| st_linetocurve                   | geometry      |
| st_locatealong                   | geometry      |
| st_locatebetween                 | geometry      |
| st_locatebetweenelevations       | geometry      |
| st_longestline                   | geometry      |
| st_makeenvelope                  | geometry      |
| st_makeline                      | geometry      |
| st_makepoint                     | geometry      |
| st_makepointm                    | geometry      |
| st_makepolygon                   | geometry      |
| st_makevalid                     | geometry      |
| st_memcollect                    | geometry      |
| st_memunion                      | geometry      |
| st_minimumboundingcircle         | geometry      |
| st_minimumclearanceline          | geometry      |
| st_mlinefromtext                 | geometry      |
| st_mlinefromwkb                  | geometry      |
| st_mpointfromtext                | geometry      |
| st_mpointfromwkb                 | geometry      |
| st_mpolyfromtext                 | geometry      |
| st_mpolyfromwkb                  | geometry      |
| st_multi                         | geometry      |
| st_multilinefromwkb              | geometry      |
| st_multilinestringfromtext       | geometry      |
| st_multipointfromtext            | geometry      |
| st_multipointfromwkb             | geometry      |
| st_multipolyfromwkb              | geometry      |
| st_multipolygonfromtext          | geometry      |
| st_node                          | geometry      |
| st_normalize                     | geometry      |
| st_offsetcurve                   | geometry      |
| st_orientedenvelope              | geometry      |
| st_patchn                        | geometry      |
| st_point                         | geometry      |
| st_pointfromgeohash              | geometry      |
| st_pointfromtext                 | geometry      |
| st_pointfromwkb                  | geometry      |
| st_pointn                        | geometry      |
| st_pointonsurface                | geometry      |
| st_points                        | geometry      |
| st_polyfromtext                  | geometry      |
| st_polyfromwkb                   | geometry      |
| st_polygon                       | geometry      |
| st_polygonfromtext               | geometry      |
| st_polygonfromwkb                | geometry      |
| st_polygonize                    | geometry      |
| st_project                       | geography     |
| st_quantizecoordinates           | geometry      |
| st_removepoint                   | geometry      |
| st_removerepeatedpoints          | geometry      |
| st_reverse                       | geometry      |
| st_rotate                        | geometry      |
| st_rotatex                       | geometry      |
| st_rotatey                       | geometry      |
| st_rotatez                       | geometry      |
| st_scale                         | geometry      |
| st_segmentize                    | geography     |
| st_segmentize                    | geometry      |
| st_seteffectivearea              | geometry      |
| st_setpoint                      | geometry      |
| st_setsrid                       | geography     |
| st_setsrid                       | geometry      |
| st_sharedpaths                   | geometry      |
| st_shiftlongitude                | geometry      |
| st_shortestline                  | geometry      |
| st_simplify                      | geometry      |
| st_simplifypreservetopology      | geometry      |
| st_simplifyvw                    | geometry      |
| st_snap                          | geometry      |
| st_snaptogrid                    | geometry      |
| st_split                         | geometry      |
| st_startpoint                    | geometry      |
| st_subdivide                     | geometry      |
| st_swapordinates                 | geometry      |
| st_symdifference                 | geometry      |
| st_symmetricdifference           | geometry      |
| st_tileenvelope                  | geometry      |
| st_transform                     | geometry      |
| st_translate                     | geometry      |
| st_transscale                    | geometry      |
| st_unaryunion                    | geometry      |
| st_union                         | geometry      |
| st_voronoilines                  | geometry      |
| st_voronoipolygons               | geometry      |
| st_wkbtosql                      | geometry      |
| st_wkttosql                      | geometry      |
| st_wrapx                         | geometry      |
+----------------------------------+---------------+
SELECT 187
