To reproduce, I was running wp v < 5.0 and the gutenberg plugin v2.6.0. Jetpack was bleeding edge. In the editor I searched for contact form and there were no Jetpack block suggestions.

Is this related to a version check?

Since a lot of the development of blocks happened before 5.0 was released I expected the block picker to work and show me contact form, etc.

cc @jeherve and @lezama