I needed to move my boards from Trello to Gitlab. It migrates the cards (issues), its columns (label), card checklists, card discussion and links to the attachments. While this solution may not compete with professional options, if you only have a couple of free boards, it might alleviate the pain.

pip install git https://github.com/e3rd/trello_json2gitlab.git

• a JSON file, exported from a trello board
• Gitlab Access Token: https://gitlab.com/-/user_settings/personal_access_tokens

Either define the token in an ".env" file or put it as an environmental variable:

GITLAB_TOKEN=... trello_json2gitlab.py TRELLO_JSON_PATH [GITLAB_PROJECT_ID] [GITLAB_URL]
GITLAB_TOKEN=... trello_json2gitlab.py downloaded.json  123456 https://gitlab.com