Charmander906's Levels adds stat levels that players can increase in order to boost their abilities.
By spending a certain number of experience levels, you can increase a stat level by one, to a maximum of 20. These stats last permanently for each player individually.

Strength:

Each level gives +1 base attack damage.

At level 10, your attacks inflict poison 1.

At level 20, your attacks inflict wither 2 instead of poison 1.

Vitality:

Each level gives +2 base max health (1 heart).

At level 10, you gain permanent regeneration.

At level 20, you gain an extra life that revives you upon death. This extra life recharges after 10 minutes or upon respawn.

Defense:

Each level gives +1 base armor.

At level 10, you gain +10 base knockback resistance.

At level 20, you gain permanent fire resistance.

Agility:

Each level gives +0.005 base movement speed (a normal player has 0.1 for reference).

At level 10, you gain permanent jump boost 1.

At level 20, you gain permanent jump boost 2.

Expertise:

Each level gives +4% chance for a tool to not reduce durability.

At level 10, you gain permanent haste 1.

At level 20, you gain permanent haste 2.

Intelligence:

Each level gives +2 xp from mob kills.

At level 10, You gain access to a pool or mana that also increases every level of Intelligence. You gain 3 spells that you can cast to start with: An evoker fang attack, a leap, and a barrier.

At level 20, You gain access to 3 new spells: A fireball, a teleport, and a heal.