Pay a set monthly fee for unlimited games?
Set up a direct debit for a monthly fee so you can play unlimited times per month.
Membership packs are now available for some games at the platform.
I like the membership card or log in idea, though this'd need quite a bit of work and focus to it.
Can I suggest a regular game discount or recurrent booking for example, it'd be easier to work with an specific venue or game you prefer to join more often.