The only routine maintenance thing I with my own horses is Pentosan or Adequan, but I work for an upper level eventer and with ten horses, she does almost everything to someone.
Icing is sort of an as necessary-- the older horses with issues get their front legs done pretty much any time they gallop or jump, the upper level horses without major issues get done after xc or a school or gallop on hard ground, the young ones get done only if they have an injury. One horse does wear the Ice Vibe boots-- I like them because they’re easy but not sure I would bother otherwise. Some get the tub, others just get regular ice boots-- mostly the Professional’s Choice ones with ice in the pockets instead of the gel packs.
Pretty much everyone gets Adequan regularly and the upper level horses get Legend before a big competition. I know that some people do shockwave as routine, but I haven’t seen it-- a couple of horses did get their backs done a few times but without much result, but other than that I’ve only seen it used for acute injuries. It’s expensive unless you can DIY and they really shouldn’t compete or train hard immediately after, which I think limits its usefulness for routine use (assuming you are ethical about the horse’s welfare).
I would say the big things I see a lot you haven’t listed are 1) Osphos-- is now being given as maintenance in many horses on a yearly basis 2) Lasering-- we use the Revitavet laser on everything from wounds/ abscesses to soft tissue issues to chronic injuries and it does seem to help 3) massage blanket (not sure I am a huge believer in this one as the horses seem to mostly find it annoying, but then I’m not riding them after)