The horizontal category bar might look quite nice, but I don't find it very usable:

• Only a few categories shown at once
• No fine tuning of the kinds of categories one might be interested in

My suggestion

This vertical listing in the sidebar would only show when viewing the contributions (in the reviewed and the to be reviewed sections). Of course the checked categories get shown, while the others get filtered out.

The syntax

<li> 
    <a class="Sidenav__item--active" aria-current="true" href="/">
        <i class="iconfont icon-headlines"></i>
        
        Contributions
        
    </a>
    <ul>
        <li>
            <label class="ant-checkbox-wrapper">
                <span class="ant-checkbox ant-checkbox-checked">
                    <input type="checkbox" class="ant-checkbox-input" data-__meta="[object Object]" value="on">
                    <span class="ant-checkbox-inner"></span>
                </span>
                <span>
                    <span>
                        <i class="anticon anticon-bulb"></i>
                        Suggestions
                    </span>
                </span>
            </label>
        </li>
        <li>
            <label class="ant-checkbox-wrapper">
                <span class="ant-checkbox ant-checkbox-checked">
                    <input type="checkbox" class="ant-checkbox-input" data-__meta="[object Object]" value="on">
                    <span class="ant-checkbox-inner"></span>
                </span>
                <span>
                    <span>
                        <i class="anticon anticon-copy"></i>
                        Sub-Projects
                    </span>
                </span>
            </label>
        </li>
        <li>
            <label class="ant-checkbox-wrapper">
                <span class="ant-checkbox ant-checkbox-checked">
                    <input type="checkbox" class="ant-checkbox-input" data-__meta="[object Object]" value="on">
                    <span class="ant-checkbox-inner"></span>
                </span>
                <span>
                    <span>
                        <i class="anticon anticon-code"></i>
                        Development
                    </span>
                </span>
            </label>
        </li>
        <li>
            <label class="ant-checkbox-wrapper">
                <span class="ant-checkbox">
                    <input type="checkbox" class="ant-checkbox-input" data-__meta="[object Object]" value="on">
                    <span class="ant-checkbox-inner"></span>
                </span>
                <span>
                    <span>
                        <i class="anticon anticon-eye-o"></i>
                        Bug Hunting
                    </span>
                </span>
            </label>
        </li>
        <li>
            <label class="ant-checkbox-wrapper">
                <span>
                    <span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;...</span>
                </span>
            </label>
        </li>
        <li>
            <label class="ant-checkbox-wrapper">
                <span class="ant-checkbox ant-checkbox-checked">
                    <input type="checkbox" class="ant-checkbox-input" data-__meta="[object Object]" value="on">
                    <span class="ant-checkbox-inner"></span>
                </span>
                <span>
                    <span>
                        <i class="anticon anticon-edit"></i>
                        Copywriting
                    </span>
                </span>
            </label>
        </li>
    </ul>
</li>