You can have up to 1,000 tables per base, according to this support page.
However, if you get anywhere close to the limit, you probably should revisit your base design.
Here are some other limits that various people find restrictive:
The limit on automations runs is currently a monthly limit. The quota resets each month. If you hit the limit during the middle of the month, there is no way to buy more runs. Some people who have used up all their runs due to unusual situations/errors have been able explain the situation to support and get more automation runs for that particular month.