Without GitHub CLI🔗

http https://api.github.com/user/repos "Authorization:token $GITHUB_TOKEN" per_page==100 type==owner \
    | jq '.[] | .full_name' \
    | fzf -m \
    | xargs -I '{}' http DELETE https://api.github.com/repos/'{}' "Authorization:token $GITHUB_TOKEN"

needs:

• jq
• httpie
• fzf

Tweak this part to customise the query

    | jq '.[] | .full_name' \

If you want to only list repos that are a fork and is a template repo:

    | jq '.[] | select(.fork==true) | select(.is_template==true) | .full_name' \

More info on githubs documentation on the repo object

With GithubCli🔗

[!NOTE] this requires a personal access token with delete_repo scope

gh auth refresh -s delete_repo

gh repo list \
    --json name \
    --limit 100
    --jq "-r '.[].name'" \
| fzf -m \
| xargs -I '{}' gh repo delete '{}'