Avoid "Mod Collector" websites that claim to have "Every mod ever made." These are 99% malware. If you download a .exe claiming to be a Sims mod, delete it immediately.
mod adds dark, dramatic events like illness or crime to the game but is part of the mainstream modding community. Fall/Seasonal Mods
: Focuses on realistic adult relationships, menstruation cycles, and attraction systems.
The "Fallen Mods" series in The Sims is a collection of mods (modifications) created by fans that can enhance or alter gameplay. Since there isn't a specific "Fallen Mods Sims" game, I'll assume you're referring to popular Sims mods that have gained significant attention.