I've tried many different kinds over the years due to stored cars and bikes. My personal choice is the BatteryMinder brand.
There are several models available, for varying specific needs:
Avoid Battery Sulfation with a Desulfating Battery Charger | BatteryMINDers
For the record, I have no affiliation or business dealings with the company, I'm just recommending what I've found to be the best option, IMO.