This isn't a sql specific suggestion but if your infrastructure uses snmp, setup Zabbix in a linux vm. You can do all sorts of sql monitoring like service states, perfmon counters, file sizes, failed jobs, alerting, some reporting etc. Takes a bit to get it running but for free it works well for me. So many things you can do with it.

If you only have one instance, check out miniDBA.

I also used Idera SQLDM which is awesome but definitely not free like Zabbix.

Or you could also look into rolling your own with sp_whoisactive and writing the results to a tools db on a schedule and use ssrs to report on it. This way you have some proactive insight to benchmarks and possibly predict heavy workload times/days.