Boundaries for List:
File Size: 2GB per item.
Document Count: A flat count of 30,000,000 items per library.
Item Count: This is also limited to 30,000,000 items per list.
List View Threshold: 5,000 items per view.
For Site Collection Threshold:Recommended number of site collections per farm is 500,000 Personal Sites plus 250,000 for all other site templates
For Site: The maximum recommended number of sites and subsites is 250,000 sites.
You can disable throttling at list level but this isn't optimal as you'll see performance issues when sending unoptimized queries to the list.
Please follow this link for avoiding such situations