With modern car keys, be veeeery careful of how much weight you put on it. The things are plastic including where the keyring goes through, and the wifes 2013 Toyota Camry key cracked from too much stuff on the keyring. Those all electric smart keys are expensive to replace!
I keep any keychain knife down to 58mm. But...I've stopped keeping a keychain knife on my keys with the new car. Car key, house key, Fenix E01 and thats it. And I'm rethinking the Fenix. My old Toyota Tacoma was a 2001, and it had an all metal key. This 2019 Corolla is all plastic. I ain't gonna chance it.