Update: Boosts have been changed from double exp rates and drop rates to only double drop rates. The first thread and the wiki has been updated accordingly with the info below. Note: Currently boosted monsters will remain the same (double exp/drops) until their boost time expires.
Donation to Boost a Monster:
For $10.00 you can select a monster to boost. The monster will for 2 months (60 days) have doubled drop rate (including card)!
Restrictions: Your selected monster cannot be a MVP or a mini-boss. It must spawn naturally. You cannot pick a monster that is currently Monster of The Moment if it already has a drop rate boost. You also cannot pick a monster already boosted by another donation. Speak to a GM is you are unsure about a monster's eligibility.
Edit, April 16th 2017:
For $10.00 you can select a monster to boost. The monster will for 2 months (60 days) have doubled drop rate (including card)!
Restrictions: Your selected monster cannot be a MVP or a mini-boss. It must spawn naturally. You cannot pick a monster that is currently Monster of The Moment if it already has a drop rate boost. You also cannot pick a monster already boosted by another donation. Event monsters are at GMs discretion. Speak to a GM beforehand to confirm a monster's eligibility.