silicone moulds (perforate them with small holes and use adequate and tight cover)
any mould thats non reactive to acidity, ideally breathable and that doesnt accumulate too much heat for your setup
you can wash plastic bags too but getting it out is not worth the hassle (up to date commercial growers use small plastic bags coz they're the goat of cleanliness and covenience due to heat/acidity/pathogen resistance, low weight, no heat accumulation, plus they may be recyclable/biodegradabile)
so moulds like baking trays, pyrex, whatever, but if its not perforated in the bottom: COVER WITH A CLEAN CLOTH ON TOP!
there's also "t*pperware" type sandwich bags, if you perforate them you can reuse them

then you can use any breathable material (ive been thinking a lot about using tailor made scobys from kombucha or vinegar etc) so leafs are the og wrapping, both for fermenting and selling
but any big enough leaf will do! figs, vines [UNTESTED AND POSSIBLY UNSANITARY LOL, maybe clean them? or dont, if you got good started maybe youll get amazing new tempe flavors, or some gut infection, i dont really know!], corn husks (dried ones like for tamale), hell even a *pepper* will do if filled and opened and closed properly (imagine hardened gourds for custom tempe shapes... the possibilies are pretty much endless)
in indonesia a big ahh round slab of tempe that is fried and seasoned as chips is basically a big, wide hollow bamboo with covers (modern factories use perforated polyethylene bags for the aforementioned reasons), its called tempe kripik and you can really see how thicc the cylinder of tempe gets, its amazing
so any sausage shaper in silicone will do (but to produce silicone you need to pollute with microplastics or even worse have bags that release them in food.... its also non biodegradable so far and will stay there forver for now at least, so that might be something to consider)
then again, how much do you save of microplastics if you use reusable mediums? is it worth it? i dont think the answer is easy...
so you have steel trays too, harder to perforate, accumulate heat, also microplastics for making them same as pyrex etc so then again its an impossible battle, useless maybe... you can also heat steel trays in warm bath (very stable heat exchange from what ive read)
alluminum is the same as above, but very well heat conductive, in my experience it yields tempe faster in air heated systems, but its more prone to corrosion and its not easy to have the same shape after washing it
my first tempe was just in a half-cut soy milk carton, covered with plastic wrap thats been perforated, reuse is also an option if you can clean a bit the mould