Any open-source admin UI for quartz.NET

Check out this blog. He describes a few that worked for him and few others he investigated.

Once you know how to use the Quartz API (Example 12 - Client really helped me), it's not too difficult to extract whatever information you want.

Check out this other question: Combining Quartz.Net with UI.

QuartzNetWebConsole and crystal-quartz seem to be more active projects. Both are open-source and have NuGet packages available.

I recently published new alternative web UI for Quartz.NET. You can manage jobs, triggers, calendars and most of the API which IScheduler provide. It is pluggable into existing OWIN and ASP.NET Core application or it creates embedded web server on it own. You can put strongly typed values to JobDataMap or edit existing JobDataMap of job or trigger.

https://github.com/jlucansky/Quartzmin

It seems that currently CrystalQuartz is the best fitting solution here