That's a fabulous idea, and I really like your intention of appreciating our HR folks, who often get ignored since they are the organizers/volunteers. I have felt the same at times but could not take further steps. It's a really appreciable thought but a bit tough to innovate further, as HR are the people who always come up with one idea or another. As per my knowledge, I would like to propose the following points.
Engage with the Company's Vision and Mission
Engage them with the company's vision and mission, be transparent with management practices, and open them up for decision-making discussions.
Appreciate Small Activities
Appreciate their small activities, where they do not expect any recognition. You may overlook appreciation for a Senior Manager's closure or practice implementation but not for dealing in a smart way with client/employee interaction.
Trust and Challenge
Trust them and provide challenging work, push them beyond their current knowledge levels, and make them realize they can do a lot more than they think.
Internal Awards and Fun Activities
Provide awards within the internal team, ensuring each talent is equally recognized and rewarded. Organize some fun activities involving the entire organization.
Career Aspirations and Mentorship
Have conversations with them about their career aspirations, mentor them in those aspects, and guide them towards a better path. Maintain a balanced work-life relationship with them.
Be an Ideal Role Model
Last but not least, you should be an ideal role model to them in all aspects and influence them with your way of managing things. That's all the followers would expect from their reporting person in a general scenario.
Regards.