Nutricote Fertilizer 18-6-8
Nutricote 18-6-8 is a slow-release pellet fertilizer, basically the same idea as Osmocote. It's what I use for Drosera regia (3–4 pellets in the soil every 6 months), and it also works for Nepenthes, Roridula (a few pellets in the soil, not too many) and regular tropical houseplants.
For Nepenthes, I only drop a single pellet into a pitcher that's already starting to dry, since too much fertilizer can burn the pitcher.