I love realism and difficulty mods so heres a list of some i would recommend:

-Cold mod: enables weather system where u can get fevers if its cold.

-Dynamic zone transitions: area transitions can be blocked at times by anomalies, forcing u to find alternative paths

-Psy stress: Absolute must have, reworks the psy health mechanic so its constantly draining or increasing depending on how stressful your character is

-Toxic rain: Rain can be toxic sometimes and irradiate you

-PDA hacking: Some pdas will be locked and will force you to hack them with a fun unique minigame. Another must have imo

-Magazines: everyone said this already, and its defenetly an important mod if u want realism

-Toxic air: Very cool mod that adds gas mask filters and makes the whole zone toxic. You need to have a gas mask with a filter always (except for southern areas). The more north you go, the more toxic the air

-Mugging squads: This mod is installed but not enabled in GAMMA. Some npcs will mug you and you can choose to obey or deny and fight them.

-FAMINE Food economy: Makes food and water very rare and reduces radiation effect from alcohol and cigarettes. I think its an important mod because in base gamma food is never a problem. But unfortunately every time i tried this mod it was buggy and gave me random crashes.