@Alejandro-Villena
Per @Lazar-Demin 's suggestion, this is a good starting list, but you'll need to add for modules you installed.

In this order (Base and Light are last to avoid dependency errors):
opkg python3-asyncio - 3.6.0-2
opkg python3-codecs - 3.6.0-2
opkg python3-ctypes - 3.6.0-2
opkg python3-dbm - 3.6.0-2
opkg remove python3-decimal - 3.6.0-2
opkg remove python3-distutils - 3.6.0-2
opkg remove python3-email - 3.6.0-2
opkg remove python3-gdbm - 3.6.0-2
opkg remove python3-logging - 3.6.0-2
opkg remove python3-lzma - 3.6.0-2
opkg remove python3-multiprocessing - 3.6.0-2
opkg remove python3-ncurses - 3.6.0-2
opkg remove python3-openssl - 3.6.0-2
opkg remove python3-pydoc - 3.6.0-2
opkg remove python3-sqlite3 - 3.6.0-2
opkg remove python3-unittest - 3.6.0-2
opkg remove python3-xml - 3.6.0-2
opkg remove python3-light - 3.6.0-2
opkg remove python3-base - 3.6.0-2