I just want to update this old discussion to point out that there is now a package module that makes this more straightforward

- name: get the rpm or apt package facts
  package_facts:
    manager: "auto"

- name: show apache2 version
  debug: var=ansible_facts.packages.apache2[0].version

Use the module package_facts. You'll get a dictionary of installed packages in the variable ansible_facts.packages. For example,

    - package_facts:
    - debug:
        msg: "{{ ansible_facts.packages[item]|
                 map(attribute='version') }}"
      loop:
        - firefox
        - libwebp6
        - thunderbird
      when: ansible_facts.packages[item] is defined

gives in Ubuntu

ok: [localhost] => (item=firefox) => 
  msg:
  - 88.0.1+build1-0ubuntu0.20.04.2
ok: [localhost] => (item=libwebp6) => 
  msg:
  - 0.6.1-2
ok: [localhost] => (item=thunderbird) => 
  msg:
  - 1:78.8.1+build1-0ubuntu0.20.04.1

The results are lists because more versions of a package might be installed. If you want to take the first items add the filter first to the pipe

    - debug:
        msg: "{{ ansible_facts.packages[item]|
                 map(attribute='version')|first }}"
      ...

If you put the list of the packages into a variable. For example,

  packages: [firefox, libwebp6, thunderbird]

you can declare the dictionary package_versions

  package_versions: "{{ dict(packages|
                             zip(packages|
                                 map('extract', ansible_facts.packages)|
                                 map('map', attribute='version'))) }}"

gives

  package_versions:
    firefox:
    - 88.0.1+build1-0ubuntu0.20.04.2
    libwebp6:
    - 0.6.1-2
    thunderbird:
    - 1:78.8.1+build1-0ubuntu0.20.04.1

- hosts: localhost

  vars:

    packages: [firefox, libwebp6, thunderbird]

    package_versions: "{{ dict(packages|
                               zip(packages|
                                   map('extract', ansible_facts.packages)|
                                   map('map', attribute='version'))) }}"

  tasks:

    - package_facts:

    - debug:
        msg: "{{ ansible_facts.packages[item]|
                 map(attribute='version')|first }}"
      loop:
        - firefox
        - libwebp6
        - thunderbird
      when: ansible_facts.packages[item] is defined

    - debug:
        var: package_versions

Neither list nor name parameter of yum says that wildcards can be used. Quoting description of parameter list:

Package name to run the equivalent of yum list package against. In addition to listing packages, use can also list the following: installed, updates, available and repos.

To list installed packages use

jsonquery: "results.packages_installed[?yumstate=='installed'].name"

Packages in the data results.packages_installed at server1, you posted, are available. Then

- set_fact:
    packages_available: "{{ abrt_packages|json_query(jsonquery) }}"
  vars:
    jsonquery: "results.packages_installed[?yumstate=='available'].name"
- debug:
    var: packages_available

gives (abridged):

"packages_available": [
    "abrt-addon-ccpp", 
    "abrt-addon-kerneloops"
]

ansible_facts.packages is a dictionary. There are no keys in that dictionary named OB2* nor OB2 since no package has this exact name.

If you want to get all keys which names start with the string "OB2", one way is to filter out all others.

• Transform you dict to a key/value list with the dict2items filter
• Use the selectattr filter and apply the match test to find the relevant entries.
• Since the key name is also contained in the parameter name inside each element in the value list , you can retain only the value using the map(attribute='someattr') filter
• Last, flatten the list to get one single list containing all packages version

Here is a playbook illustrating the concept. For the example, I used as a prefix "zlib". Just change it back to whatever suits your needs

 ---
 - hosts: localhost
   gather_facts: false
 
   vars:
     package_prefix: "zlib"
 
     filtered_packages: "{{ ansible_facts.packages | dict2items 
       | selectattr('key', 'match', package_prefix) 
       | map(attribute='value') | flatten }}"
 
   tasks:
     - name: gather package facts
       ansible.builtin.package_facts:
 
     - name: debug the raw variable
       debug:
         var: filtered_packages
 
     - name: count relevant packages
       vars:
         pkg_num: "{{ filtered_packages | count }}"
       debug:
         msg: "There are {{ pkg_num }} packages
           which name starts with {{ package_prefix }}"
 
     - name: show some info about relevant packages
       debug:
         msg: "Package named {{ item.name }} is in category {{ item.category }}
           and has version {{ item.version }}"
       loop: "{{ filtered_packages }}"

Which gives on my Ubuntu local machine:

PLAY [localhost] *****************************************************************************************************************

TASK [gather package facts] ******************************************************************************************************
ok: [localhost]

TASK [debug the raw variable] ****************************************************************************************************
ok: [localhost] => {
    "filtered_packages": [
        {
            "arch": "amd64",
            "category": "libs",
            "name": "zlib1g",
            "origin": "Ubuntu",
            "source": "apt",
            "version": "1:1.2.11.dfsg-2ubuntu1.3"
        },
        {
            "arch": "amd64",
            "category": "libdevel",
            "name": "zlib1g-dev",
            "origin": "Ubuntu",
            "source": "apt",
            "version": "1:1.2.11.dfsg-2ubuntu1.3"
        }
    ]
}

TASK [count relevant packages] ***************************************************************************************************
ok: [localhost] => {
    "msg": "There are 2 packages which name starts with zlib"
}

TASK [show some info about relevant packages] ************************************************************************************
ok: [localhost] => (item={'name': 'zlib1g', 'version': '1:1.2.11.dfsg-2ubuntu1.3', 'arch': 'amd64', 'category': 'libs', 'origin': 'Ubuntu', 'source': 'apt'}) => {
    "msg": "Package named zlib1g is in category libs and has version 1:1.2.11.dfsg-2ubuntu1.3"
}
ok: [localhost] => (item={'name': 'zlib1g-dev', 'version': '1:1.2.11.dfsg-2ubuntu1.3', 'arch': 'amd64', 'category': 'libdevel', 'origin': 'Ubuntu', 'source': 'apt'}) => {
    "msg": "Package named zlib1g-dev is in category libdevel and has version 1:1.2.11.dfsg-2ubuntu1.3"
}

PLAY RECAP ***********************************************************************************************************************
localhost                  : ok=4    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0 

Are you looking to know about all dpkg commands with options? Have a read from the below link.

15 dpkg commands to Manage Debian based Linux Servers

To List all Installed Packages

Here less is a simple text reader used to scroll through the list of packages in a new buffer that opens in the existing terminal window. The list will not be mixed with other terminal commands and output. Hit q to return to the terminal prompt. See man less for more info.

dpkg -l | less

To check whether a package is installed or not:

dpkg -l {package_name}
dpkg -l vlc

To check if the package is installed or not (for example, vlc). If installed, launch the package:

dpkg -l | grep vlc

Show the location where the package is installed. The -S (capital S) stands for "search"

sudo dpkg -S {package_name}
sudo dpkg -S skype

To use Grep to search:

dpkg -l | grep {keywords}
dpkg -l | grep pdf