The values come from the tooltips on BianKO's mob and exchange pages. None of these belts has a Required Level or stat requirement line; Belt of Quickness (Required Level 55) is the exception.

Belts with attack power or dodge

BianKO belts: special effect, Defense and source
BeltAttack power increaseDodge increaseDefenseOther linesSource
Skeleton Belt 50% — 30 Dagger, Club, Spear defense 10; Resistance to Glacier 30 32 mob records; Forgotten Accessory Box 0.024%
String of Skulls(+1) 50% — 12 HEA 9, STR 9; Dagger, Club, Spear defense 6; Glacier 33 Yellow Sand, Pidama, Worm, Isiloon, Felankor
String of Skulls 50% — 10 HEA 5, STR 5; Dagger, Club, Spear defense 5; Glacier 30 Dark Fragment of Pride/Gluttony, colored Gems
Elf Belt 20% 20% 30 DEX 10 32 mob records
Helt of Harpy — 50% 20 Sword, Ax, Arrow defense 10; Resistance to Lightning 30 Tree Ghost King (5053); Forgotten Accessory Box 0.217%
Kekuri Belt — 30% 30 Resistance to Flame 30 Kekurikekukaka (111, 116, 117, 161), Tree Ghost King
Fire / Ice / Lightning Belt — 30% — Matching resistance 50 Talos (2406, 2407, 2455), Tree Ghost King

Skeleton Belt and String of Skulls(+1) give the same 50% attack power. Skeleton Belt has 30 Defense against 12 on String of Skulls(+1), while String of Skulls(+1) adds HEA 9 and STR 9. Elf Belt matches Skeleton Belt's 30 Defense and adds DEX 10.

Belts with HP, MP and stats

Stat belts (tooltip values)
BeltHPMPStatOther
Sash of Sorrows(+1) 75 75 STR 14 Defense 2; Flame 23, Glacier 33
light Belt of Life(+1) 75 75 HEA 14 Defense 2; Flame 23, Glacier 33
Belt of Dexterity(+1) 75 — DEX 12 Defense 2
Judicious Belt 50 50 DEX 10 Flame 20, Glacier 30
Belt of Strength / Dexterity / Life 50 — STR / DEX / HEA 8 —
Belt of Intelligence — 50 INT 8 —
Crystal belt — 50 Magic Power 10 —
Bronze Belt — — — Defense 20; defense 5 against six weapon types

The most HP and MP, 75 each, is on the +1 belts, and those only drop from the group lists of Yellow Sand (9011), Pidama (9537), Worm (700), Isiloon (5551) and Felankor (7035). Belt of Curse gives -5 to every stat, -30 Defense and -50 HP and MP, in return for +30 to resistances (+50 curse).

Where Skeleton Belt and Elf Belt drop

Both belts share the same 32 mob records in their group drop: Berk, Barkira, Shaula, Lesath, Duke, Bach, Javana, Samma, Talos, Orc Bandit Leader, Tree Ghost King, Ultima, Grudge, Query, [PARTY] Rampage Orc, War Monument, TREE BOSS, Felankor (9299), Medusa, Ice Golem, Blue Phoenix, Hades and more. The lowest-HP ones:

Lowest-HP mob records that drop Skeleton Belt and Elf Belt
Mob (id)LevelHP
Berk (607) 55 29,155
Garges (9698) 55 65,000
Talos (2407) 140 70,000
Barkira (608) 60 73,574
Dragon Tooth (1107) 80 76,380
Bone Collecter (1106) 60 80,000
Ice Golem (9930) 83 82,041
Javana (1305) 65 84,520

Mob pages show no drop rate or zone. Old Skeleton Belt and Old Elf Belt carry the same stats but bind to your character once equipped; the Old accessory guide covers that.

FAQ

Skeleton Belt or String of Skulls?
Both raise attack power by 50%. Skeleton Belt stands out with 30 Defense, while String of Skulls(+1) has 12 Defense but adds HEA and STR.
Where does Helt of Harpy drop?
On the mob pages only Tree Ghost King (5053) has it in its group drop. On the exchange side it's in Forgotten Accessory Box at 0.217%.
Can you upgrade a belt?
Accessory upgrades on BianKO use Accessory Compound Scroll and cap at +3; the site doesn't say whether belts are included. It only shows stats for plain and +1 belts.
What's the belt drop rate?
The site doesn't list it. Percentages in the exchange boxes don't add up to 100%, so read them as relative odds.

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