A PostgreSQL view that combines the relation size, the size of its indexes, the size of its toast table, and the size of the toast table indexes, combines them to give you a total table size.

table_sizes.sql

CREATE OR REPLACE VIEW public.table_sizes AS
WITH tables AS (
        SELECT a.oid, b.nspname, a.relname, a.reltoastrelid, pg_relation_size(a.oid) AS size
          FROM pg_class AS a
          JOIN pg_namespace AS b ON b.oid = a.relnamespace
         WHERE a.relkind = 'r'
           AND b.nspname NOT IN ('pg_catalog', 'information_schema')),
    indexes AS (
        SELECT i.oid, n.nspname, i.relname AS idxname, c.oid AS reloid, c.relname AS relname,
               pg_relation_size(i.oid)  AS size
          FROM pg_index AS x
          JOIN pg_class AS c ON c.oid = x.indrelid
          JOIN pg_class AS i ON i.oid = x.indexrelid
          JOIN pg_namespace AS n ON n.oid = c.relnamespace
         WHERE c.relkind = 'r'::char
           AND i.relkind = 'i'::char),
    toast AS (
        SELECT a.oid, b.nspname, a.relname, pg_relation_size(a.oid)  AS size
          FROM pg_class AS a
          JOIN pg_namespace AS b ON b.oid = a.relnamespace
         WHERE a.relkind = 't'),
    toast_indexes AS (
        SELECT i.oid, n.nspname, i.relname AS idxname, c.oid AS reloid, c.relname AS relname,
               pg_relation_size(i.oid) AS size
          FROM pg_index AS x
          JOIN pg_class AS c ON c.oid = x.indrelid
          JOIN pg_class AS i ON i.oid = x.indexrelid
          JOIN pg_namespace AS n ON n.oid = c.relnamespace
         WHERE c.relkind = 't'::char
           AND i.relkind = 'i'::char),
    totals AS (
        SELECT a.nspname, a.relname,
               a.size AS table_size,
               CASE WHEN sum(b.size) IS NULL THEN 0 ELSE sum(b.size) END AS index_size,
               CASE WHEN sum(c.size) IS NULL THEN 0 ELSE sum(c.size) END AS toast_size,
               CASE WHEN sum(d.size) IS NULL THEN 0 ELSE sum(d.size) END AS toast_index_size
          FROM tables AS a
          LEFT JOIN indexes AS b ON b.reloid = a.oid
          LEFT JOIN toast AS c ON c.oid = a.reltoastrelid
          LEFT JOIN toast_indexes AS d ON d.reloid = c.oid
         GROUP BY a.nspname, a.relname, a.size)
    SELECT nspname AS namespace,
           relname AS table,
           pg_size_pretty(table_size) AS table_size,
           pg_size_pretty(index_size) AS index_size,
           pg_size_pretty(toast_size) AS toast_size,
           pg_size_pretty(toast_index_size) AS toast_index_size,
           pg_size_pretty(table_size + index_size + toast_size + toast_index_size) AS total_size
      FROM totals
     ORDER BY (table_size + index_size + toast_size + toast_index_size) DESC;