I got some black milk crates from TRACTOR SUPPLY. I modified them, though. Would post pics but don’t know where to “hunt” for them at the moment. I took out some of the plastic on the sides — wanted to have nice big openings for the fish to swim through [have had some of my larger goldfish get trapped]. Also, sanded all rough/sharp edges for the same reason (and to protect the liner). To keep the pots from sliding off the crate, I made some little brackets with PVC pipe.
OK, went out and took more pics. This was made specifically to hold the WallyWorld “oil pan” lily pots. I had problems with the pots sliding off the crate — brackets zip-tied on prevent that. Also, top of crates would be top-heavy and crates would fall over — zip-tied a heavy pot inside the crate for ballast. May all be overkill, but were good solutions for issues I had.