The following are some of youtube ad format available when you start monetizing your ads
1. Display ads
2. Overlay ads
3. Skippable video ads
4. Non-skippable video ads
5. Bumper ads
6. Sponsored cards
Ads option 1, 2 and 3 are available be default but 4,5,6 are not available. In order to enable Non-skippable video ads you need to wait for it to appear automatically. If you can’t currently enable non-skippable in-stream ads as an ad format for your monetized videos, you may submit a request to enable this ad format here. YouTube will review your request and take action accordingly.
Please note that while non-skippable InStream ads may generate higher revenue than other ad formats, they also have a higher abandonment rate. Enabling this ad format across your videos can lead to lower video views and watch time. It’s up to you to determine the best balance between views/watch time and revenue for your channel, and you can use the Ad Performance and Views reports in YouTube Analtyics to help you make that decision.