My last job used https://github.com/opserver/Opserver which had a pagerduty tab. Nice being able to see who was the on call and have instructions for when/how to page out.
It also has a "take on call for the next hour" button, which (for logged in users that matched a pagerduty user) would create an override for the next hour. Really handy when you are starting a change window and don't want to risk waking up the on call.
Looking at opsgenie API, it shouldn't be too difficult to build a version of PagerBeauty for it, but I'd need API keys to for testing. Their sandboxed app (app.sandbox.opsgenie.com) doesn't allow me to add an API integration so I can't generate the test keys. I'll ask on their community forums or send a message to support.
Today I got v1.0.0 out. It can display ongoing incidents and supports basic grafana theme. At my work we use this on Datadog dashboards.
Free and opensource.