A single Preview Crate: Gloomspore will be a possible reward as part of the April 2020 daily rewards, given for logging in for 21 days that month. Unlike regular Gloomspore crates, the Preview Crate pulls from a limited pool of potential rewards. They can be distinguished from regular Gloomspore crates by their blue and grey color, as opposed to the usual brown.
Notably, these crates are guaranteed to grant one of five pets modeled after the Apex-level mounts of the Gloomspore Season released in March 2020. The pets found in the preview crates are not available in regular Gloomspore Crates.
The possible rewards are as follows, grouped by rarity with Legendary rewards being the rarest:
Duplicate Legendary rewards grant from extraction.33
Unwanted Fine Rewards grant from extraction.1
Unwanted Common Rewards grant from extraction.1