DC lighting powered “directly” (i.e. without DC/AC conversions) by solar panels and batteries is one of the examples.
there's a pretty big initiative going on at the aachen uni by a few departments that are very much in favor of switching most building electricity demand to DC. everything will be smaller and more efficient that way, in addition to the easier integration of solar, batteries, lights, you name it. however the huge hurdle, as always, is that they're trying to replace an established and accepted system. they're facing the problem that all their tech would, at first, be niche stuff only adopted by very few people, which in turn just makes it expensive. i believe standards aren't even the issue anymore, it's now more cost and ease of replacements and such.
but yeah... it's honestly pretty dumb the way that we keep converting between AC and DC just for the fun of it. at least there's hybrid inverters now that couple battery and PV on a DC basis... but still, then I switch that over to AC, feed it into my wallbox, into the car, which turns it back into DC for the battery. I think since all the conversion steps are all 95%+ efficient, nobody seems to care, but honestly all the small stuff also adds up.
tepeo electric heat store
I saw that thing on fully charged and thought... well, that must be one of the dumbest products i've ever seen. or am i missing something? like it's literally a hot water tank with an immersion heater stuck into it, basically, yeah? so it's not especially efficient (compared to, say, a heat pump) or anything. the only thing it's got going for it is a) it's electric and b) it's probably super cheap to buy. ok i guess i see the appeal, carry on

still a bit daft to sell that as a great new greentech thing - we've had (tank-less) electric boilers for 60 years and nobody would ever claim they're green or efficient or anything.
edit: PV installations that have shit feed-in-tariffs (say from the late 2010s) here in germany quite often have an electric immersion heater added to the houses hot water storage as well, to dump any excess PV production that isn't self-consumed - since that is more economic than feeding it into the grid. but that is just ditching excess energy to help the main heating system along, not the ONLY system in place.
oh well - gotta hand it to the tepeo folks: great marketing they're doing...