Lots of sites offer parking with supplemented Ad revenue - i cannot speak to their efficacy and i hope someone else can provide insight on that.
I am the founder of DynaDomains, which is a lot like parking your domain. It allows a single domain to be subleased to multiple businesses/people all at the same time. You get a nice commission off what the lease pays per month (75% to you, typically). All done with a simple 301 redirect.
I, of course, have all my domains on that site, as well as a bunch of other domain owners who have onboarded their domains with us.
The third option is to make the domain into a profitable page with content that you can populate (via yourself or copy-writers for hire) and then sell ads on that. That is more akin to running a forum/online business so that is obviously the most high-touch solution.