If you want to have piece of mind, you should send your old employer an email, asking them to verify that they have received all outstanding equipment.
Dear [Contact X],
I have shipped all outstanding equipment to [Employer Y] and have have received notification it has been delivered.
Are you able to confirm that all equipment is accounted for and there is nothing else outstanding?
Kind regards, qu7869069
You are responsible for the equipment until it is back in possession of the employer. Unless the employer engaged the shipping company themselves, you are responsible to make sure that happens. So it doesn't hurt to get a confirmation email from the employer that everything has been delivered.