Ishikawa diagram makerfrom plain language, free.

ishikawa-beta
    Website slow after the last release
    Code
        N plus one queries on product pages
        Uncompressed hero images
        Blocking third-party script
        Debug logging left on
    Database
        Missing index on orders by user
        Migration rebuilt a large table
        Connection pool too small
    Infrastructure
        Fewer servers after autoscaling change
        CDN cache rules reset
        Cold starts on new functions
    Process
        No performance test before release
        Released at peak traffic
    Monitoring
        Latency alert threshold too high
        No dashboard for page load times
    Dependencies
        Heavier payment widget
        Analytics script loads twice