One Vita owner and NeoGAF member has discovered that even if his PlayStation Vita's 32GB card has space remaining in its storage, the system can display only up to 100 apps.
Shagg_187 shared the above photo, explaining that his card had 9GB of space left, with around 50 minis, 10 PSOne games, 20 mandatory apps, and 20 Vita or PSP games and apps. We've contacted Sony for an explanation on the numerical cap. Until then, maybe start treating your apps like children and think about which one really is your least favorite.