If it's 60lbs or more it's good, you just have to be careful with lighter stuff.
If you want to know what I use, it's Georgia Pacific 110lbs card stock, the exact one isn't on amazon, I get it at walmart.
Get as close as you can to 110lbs, if it's too flimsy, you have to be careful when handling it, and then do one layer resin outside, two on the inside. This reinforces it enough to withstand rondo. You do need to be more careful if it's too light though.
Also, don't go above 110, that's pretty much the limit conventional home printers can handle.