Bulbophyllums and Cirropetalums are great choices. Also Paphiopedilums, Phalaenopsis-type Dendrobiums (the minis, otherwise they'll outgrow your terrarium in short order), and many species orchids. Avoid Phalaenopsis. I'm not sure about Cattleyas, I think they may need a drying period, as do Oncidiums, though some species Oncs. are good, especially the minis, aka Tolumnias. BTW, orchids don't generally want lower light. The ones that need a rest period usually need a dry period, and most cool-growers prefer to be cool year-round. You should also ask on the orchids forum, and people there know a lot more than I do. =)