use of different types of solar where appropriate, we always see PV but solar thermal and bio-solar have some great uses - tanks of algae can be really good for various uses; nutrition for people and animals food and medicine ingredients such as carrageenan and agar, building materials from cellulose, biofules, bioplastic, wastewater treatment, fertilizer as well as potential future uses like being used in biodegradable electronics, as sensor materials (https://www.intechopen.com/chapters/50395) and for more advanced chemistry such as genetically engineered algae making cleaning solutions (great for cleaning solar panels), fuel for cutting tools, and of course alcohol and drug molecules (both medicinal and recreational)
Cody's Lab has some fascinating videos about his diy algae project, https://www.youtube.com/watch?v=64cEmjtwRgw might be useful as a visual reference, but basically they're tubes or tanks that sit in the sun or partial shade and grow algae.
people having a cookout on something like this https://en.wikipedia.org/wiki/Solar_cooker or using a larger one to do things like fire ceramics (to maintain and regulate temperature over the duration you'd probably want something like molten salt feeding into a refractory chamber, by controlling the flow rate and mirror focus you could get very good temperature balance) there was a great video with a guy i think in the Nevada desert who had an array which he was using to melt metal and sand casting, this would be a great way to recycle heavy infrastructure from todays society - maybe a scrapyard with mirror arrays used to recycle old cars into useful new tools, the mirrors don't need to be perfectly reflective so could simply be sheets of metal made from the scrap and polished with a windmill powered grinding plate -- the only difficult thing is getting them all to line up, this could be complex tracking gears, digital sensor and motor based systems or a slightly cleverer solution using passive solar tracking where a windowed section of the mirror surface is linked to hydrolytic containers and thermal expansion causes it to realign when one side goes dark - i've seen diy people make them that work pretty well but they're still far from perfect even the expensive industrial ones
oh nice that sounds really cool, i'm looking forward to seeing what you come up with!