The traps are as follows (IIRC - I may have 3 & 4 reversed):
Level 1: small explosion
Level 2: dart trap
Level 3: medium explosion
Level 4: Poison gas
Level 5: Biggest explosion
A. The kegs and barrels are level 1
B. The random crates (gypsy & brigand random camps) can be level 1 or level 2
C. The random chests are level 3 or level 4 (And if two chests spawn at a gypsy or brigand, one is always 3, the other 4 - the crates, barrels, and kegs spawn in place of one of the chests, sometimes, but two chests is the most common spawn)
These items (A-C) are also the random container spawns in dungeon, though typically, most areas are limited to a certain number at a time (for example, the area with static crates, by the water elementals in SW Destard level 1 always spawns 2 level 3 and 1 level 4 chest, while the spwn in the dragon-infested area can include crates, barrels and kegs on rare occasions)
D. Static crates & chests (such as in dungeons) are random 1-5. These containers will be empty when first opened, then loot will spawn in them a short time later, and keep respawning every 30-60 minutes, as long as you empty the chests - if the chest isn't emptied, it will go back to the "static empty" state when the loot decays. The loot is normal equipment, bones, body parts, scrolls (blank, up to level 8), and rarely, gems.
On a slightly different timer, the locks will reset. The lock LEVEL will change randomly each relock, so that a crate that you picked with a 95 LP may not be openable by you after a respawn, or be a level 1 that you can't gain on. TRIVIA: Before the introduction of creatures such as the Meer Eternal & Dark Father, these crates were the only source of level 8 magery scrolls, so these crates had to be repeatedly hit, for scribes & mages to get access to the spells, and then be able to cast the spells (And make scrolls for those without lockpickers).
E. "Thief" chests and crates are the ones that have multiple traps, quite often, and are in NPC areas for thieves to train on (example, Serpent's hold Blacksmith). their LP skill needed is typically very low, or in some cases, not locked at all.