This is a small datapack that adds passive effects as a possible rewards for the pufferfish skills mod (https://www.curseforge.com/minecraft/mc-mods/puffish-skills  - Not my mod, I just made this addon)

How to use:

Simply add a scoreboard command reward for your skill points (according to the minecraft version the command will change). For performance reasons the effects will only apply every 200 game ticks (10 seconds) but will be constant once applied, a small downtime window might be present if the player drinks milk or dies. By default effects won't display potion particles.

Video showcasing functionality and expected downtime:
https://streamable.com/e/wjofme

Here's the basic structure for your rewards:
scoreboard players set @s firefly.vanillaeffectname effect level

Example (definitions.json):

"rewards": [

"rewards": [ {

"type": "puffish_skills:command",

"data": {

"command": "scoreboard players add @s firefly.speed 1" } } ]

NOTE:1.18 commands are a bit more limited so the effects are limited to level 10, for 1.20+ these effects won't be limited.

Pufferfish Skills Effects Unnoficial Addon - Vanilla Effects