Finish at least 15 series in 2025. Just add the last book of a series to each prompt so the prompt is not marked completed until you have finished the series. 
There are 15 bonus prompts for those who go above and beyond. 
Edit: Okay, you all are wild. It's only March and all 30 prompts have books added. I added 10 more Bonus prompts for the overachievers.