You can use wait steps in Journey Builder, with some custom setup:
Let's say you don't want to send more than One email per week to subscribers.
Create & maintain a DE:
Query the _sent data view to grab all the subscriber keys that were communicated to in the past week, include also the latest send date for each. Add 7 days to the latest send date and include this as a third column. Push above Three attributes into a DE, and set subscriber key column to subscriber key (you may also need to connect this DE to the contact key in Data Designer, subscriber key from _sent = contact key). Automate this process to refresh daily.
Wait step in Journey Builder
Once you have the above DE automated and maintained, then you can configure a wait step in journey builder to only let through subscribers whom have the above third column in the past, otherwise wait until that is true.