I made some boxes about 10” x6” about 5” deep with rope handle loops through the ends, one for home tools and one for shoe cleaning kit, just lap jointed. Also a shop counter for a Charity shop.
Thing to note if glueing T&G together is that usually the top surfaces of the floorboards touch before the bottom edges so if not careful it won’t produce a flat board, as you cramp it up the board rises up. And of course the underside of the boards often have relieving grooves running along to help stop cupping. Ian
Pretty much anything you want to lol, I was given an old oak floor a couple of years ago, made all sorts of small items including pens but wouldn't be hard to glue some strips together, I would probably take the tongue & groove off it if I was going to do that. I just wish they had taken a bit more care when they lifted it but having said that I guess it was free lol
I made some small (approx 18" x 12") tables on 6" round wooden legs to take PC monitors as Xmas presents last year. Excellent. Legs were attached via 6mm threaded inserts. Then made another 3 as small tables to put cat food plates on. Remarkably strong items.