Altering the Owner of All Tables in PostgreSQL

You can alter the owner of multiple tables at once by scripting PL/pgSQL

alter database :database owner to :owner;
do $$ declare t text; begin
    for t in select table_name
                from information_schema.tables
                where table_schema = :schema
                    and table_catalog = :database
    loop
        execute format(
            (
                'alter table ' || :database || '.' || :schema 
                    || '.%s owner to ' || :owner
            ), t
        );
    end loop;
end $$;