Is there any command to list "local" packages? like in Synaptic GUI

Find installed packages that does not originate from any source.list or cannot be downloaded.

$ aptitude search \
  '?narrow(?or(!?origin(), ?obsolete), ?installed)'

Or short form:

$ aptitude search '~S (!~O|~o)  ~i'

• ?narrow(filter, pattern)
  Select packages which matches both filter and pattern.
• ?or(pattern, pattern)
  Matches any of the patterns or both.
• ?origin(pattern)
  Select packages with given origin.
• ?obsolete
  Matches installed packages that cannot be downloaded.
• ?installed
  Select installed packages.
• ?not(pattern) or !
  Select any package not matching the pattern.

apt list --installed labels packages as local in a way that seems to agree with your definition (see my answer here). You could filter only packages so labelled with ask, grep, etc.:

apt list --installed | awk -F/ '/local]/{print $1}'

You could also probably make a similar check using the Python APT API.

With apt-show-versions | grep -e 'No available version' -e 'newer than version' you should get the list of packages:

• without a version in any repo.
• or have higher version than the one in repo.

Probably you need to install it beforehand with sudo apt install apt-show-versions