If you're going to use Nraas mods, these are the ones I would personally recommend.
Story Progression - For obvious reasons.
Register - Can be used to reduce wild animal populations, which helps with lag. Also helps populate shops/stalls.
Overwatch - Performs game cleanup once every 24 sim hours.
Error Trap - Grabs errors, logs them and resets the sim rather than just letting the error sit there.
Saver - Fixes issues with the save system, prompts you to save every 30 mins (Save as, not just a normal save)
Traveller - Helps fix issues with going to the future or on holiday.
Traffic - Cleans up taxis, limos, etc. Can also be used to turn on/off ice cream vans and food vans.
Mover - Less useful than the others. Mostly just helps prevent issues moving house or neighbourhood.
Go Here - Helps fix routing issues.
I know that seems like a lot of mods, but they -really- help reduce lag.