Long-lining thru any dressage test/reining pattern. Beach rides/hacks when driving/footing conditions permit (and the windchill is a tad better than 40 below). Less grain (not an option for ALL horses), free choice hay, maximum turn-out, stall toys, rotate turn-out paddocks on occasion if possible (same friends, just a different view).
These activities work for me but I board at home and fully realize many boarding facilities are limited in what they can offer in terms of diversity.
I have elders that live out 24/7 and have a completely different set of issues so can’t offer anything of real substance and solution.
Sure there's right and wrong but mostly there's just a whole lotta different.