I'm notoriously over-prepared when going off road, but I'd put these at the top of the list;
First Aid Kit,
High Lift Jack
Emergency clothes / coats
Misc spare parts
1992 YJ, 401 V8, EFI, TH400, Atlas, D60s, Detroits, Warn 8274, Cage, 37 Krawlers
1997 TJ, 350 V8, EFI, TH400, Atlas 4spd, D60s, Detroits, Warn 12000, Cage, 40 Kevlars
TTC 1994, TTC 2012, Trail Tour participant.