Selaginellas would probably do well for you at that humidity - S kraussiana and S brownii are the easiest, S uncinata has an amazing blue sheen and isn't hard, and S erythropus is taller, and a pain in the butt, but a nice red color under the right light.
Pilea microphylla, P nummulariifolia and/or Pilea "glacophyllum" could work on flat areas. None grow very tall or have large leaves. P microphylla and P nummilariifolia are invasive plants in most tropical/subtropical climates, so they will definitely take off. In the same vein, Cymbillaria aequitriloba would probably do well, but gets stringy. There are, of course, many small orchids that could do well with those conditions, but they tend to be more expensive so I can't really comment on them.
There are quite a few vining ferns that would so well at that humidity, if you want an uncommon vining plant. I grow Pleopterus percussa at a lower humity (70-80) but it would probably do okay in that range. It can either work as a carpet or a scrambling vine. Lemmaphyllum microgramma, Pyrrosa nummularifolia, and Microgramma species would also work. Pellonia pulchira could vine in areas with good drainage. There are some mini Syngoniums, if you want an aroid. There are rarer small aroids, but they tend to be expensive and harder to buy (especially right now, as aroids are "in style").
If you like grass-like plants, some members of Cyperus, some tropical Carex, and most Eleocharis are rather small and would do well with wet soil.
If you want some larger plants that would up the "tropical" look, Maranta leuconeura repens , and Monstera pittieri would both be good vines. Marantas sometimes die off a bit in the winter and want less moisture, though.
As a warning if you don't know, at that humidity level you will probably need to have a plan in place to reduce the risk of mold. I've personally never had as much of a problem with it as I ought to have, but I have heard horror stories.
Last edited by f Majalis; 11-22-2018 at 03:45 AM.
Reason: Sentence got cut off