Pokemon Home explains what happens if you let your Premium Plan lapse
You may have jumped on the Pokemon Home premium plan from day one, but there might come a time where you'd rather spend the money on something else for a month or two. Wondering what happens if you let your subscription lapse? A note in Pokemon Home explains the situation.
If you deposit 31 or more Pokemon in Pokemon HOME while you have the Premium Plan, and your plan then changes to the no-cost Basic Plan, you will not be able to view or withdraw any Pokemon beyond the 30th Pokemon you deposited. By re-enrolling in the Premium Plan, you'll be able to view all the information about additional Pokemon as well as move them out of Pokemon HOME.
Remember, if you do decide to give the Premium Plan a try, your subscription is set to auto-renew. You'll have to turn that off if you'd rather handle payments on a month-by-month basis.