This information I have found in PostgreSQL docs:
Table 52-1. Contents of PGDATA
PG_VERSION A file containing the major version number of PostgreSQL
base Subdirectory containing per-database subdirectories
global Subdirectory containing cluster-wide tables, such as pg_database
pg_clog Subdirectory containing transaction commit status data
pg_multixact Subdirectory containing multitransaction status data
(used for shared row locks)
pg_subtrans Subdirectory containing subtransaction status data
pg_tblspc Subdirectory containing symbolic links to tablespaces
pg_twophase Subdirectory containing state files for prepared transactions
pg_xlog Subdirectory containing WAL (Write Ahead Log) files
postmaster.opts A file recording the command-line options the server
was last started with
postmaster.pid A lock file recording the current server PID and shared
memory segment ID (not present after server shutdown)
When I have only folder base or base+global, can I read tables data
from databases in such PGDATA via any tools or methods?