In GTA 5 Enhanced:

Game crash FIXES

Some outdated .asi mods like "ObjectSpawnUnlockNbuild.asi" can cause game crash after loading story mode, so, make sure you don't have GTA 5 Legacy 
.asi mods that aren't officially ported to GTA 5 Enhanced in the Enhanced main folder, like the "ObjectSpawnUnlockNbuild.asi"

Adding peds WILL CAUSE GAME CRASH eventually (after some number of added peds, depending on file sizes basically), so, using a gameconfig.xml 
and removing few entries from dlclist.xml will help, check this guide: https://www.youtube.com/watch?v=3QvNSnrWQ-o&t=184s

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Script errors on startup (TypeInitializationException, error file opened, error writing log, etc.)

Install this plugin case your game presents some errors when starting the mods or cant read/write .ini files:
https://www.gta5-mods.com/scripts/directstoragefix

Update your NIBMods menu and his plugins:
https://www.patreon.com/posts/22783974

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In GTA 5 Legacy

Game crash FIXES

Just like in Enhanced, added peds may cause game crash at loading or randomly when playing, the fix is similar:
https://www.patreon.com/posts/added-peds-limit-123679009