When you are selecting a baseboard sealant for your project, here are a few things to keep in mind.
Use 100% silicone for sealing exterior areas and areas subjected to frequent water or moisture (such as the bottom of baseboards on a tiled basement floor). Silicone is available in a wide variety of colours, so you will likely find one that matches your décor perfectly.
Knowing how to caulk baseboards is key but if you intend to paint the baseboard, you need to choose a paintable sealant. Pure silicone is very durable and highly resistant to moisture and mould, but it is not paintable. However, many acrylic trim sealants now have added silicone, gaining its benefits while still accepting paint.
For general purposes, a flexible acrylic latex sealant will do the job and LePage Polyfilla Trim and Baseboard Filler is an excellent choice. This formula has added silicone for extra durability and strong adhesion. You can paint it in as little as 30 minutes after application, and uncured sealant cleans up easily with water.