I've recently been getting more interested in cactuses. This was spurred by the death of my grafted moon cactus, which I'd had for about two years and I really enjoyed looking at. I ordered a 6" Pilosocereus azureus off of Etsy, which should arrive in a few days.
In the meantime though, I was out on a walk enjoying the warm weather when I saw a small pad of Opuntia polyacantha? on the side of the trail. It looked alive, but chances were very low that it would survive the upcoming cold snap seeing as it was tiny and lacked roots. I brought it home and prepared a pot for it. It's a tall pot with mesh covering the drainage hole and a shallow gravel layer on top of that, all to maximize drainage. I mixed up a basic succulent mix with pea gravel, compost, potting soil, and some orchid bark. I stuck the cactus pad about halfway into the mix and covered the mix with a thin layer of potting soil to keep the cactus upright and to ensure that the area around where the roots will soon be stays moist. Assuming it takes root and grows well, I'll plant it outside next year seeing as it's a native plant.
I've also had this planter for about 4 years. It's full of cactuses that were listed as 'small succulent' at the plant nursery. If you want to try IDing them go for it.