RotN Tweaker is a mod specifically made for the Rebirth of the Night modpack. It allows us to make some tweaks that can only be done via modding.

What this mod does:

Miscellaneous features

• Adds a config option to remove all vanilla nameplates/nametags, so that they can be replaced by another nameplate mod like Neat (a mod by Vazkii)
• Adds ability to replace torch particles with a custom texture using resource packs

Works with vanilla, GlareTorch, Quark, and Rustic torches

• Adds configurable Pyrotech machine speed modifiers when powered by BetterWithMods/BetterWithEverything axles

New potion effects

These effects come with some pre-configured settings for demonstration purposes, but are meant to be tweaked by modpacks to make the most out of them. All values, ranges, coordinates, and biomes are configurable. All effects have custom icons and some overlays included, modifiable via resource packs to suit your needs. None of these potions are craftable by default

• Webbed: Each level slows players by 25% of their speed up to 75%, and it can be entirely removed by "struggling" (pressing the movement and jumping keys). Receiving any fire damage instantly removes the webbed effect too. Has a grace period after removing it.
  • Can be applied by mobs using a mod like Rebirth of the Mobs' mob offense feature
  • Has a custom screen overlay
• Soul Stream: Removes friction and fall damage, allowing almost unlimited speed when coupled with speed buffs. Has a "fire" visual/sound effect when falling from great heights (credits to Cyclic's bounce effect)
• Clean: While active, each level is consumed to prevent an instance of configured effects affecting the player
  • Be default, protects against poison and nausea
• Sweltering/Scorching: Sweltering adds a countdown effect which raises in level while under the configured biomes, until it transforms into Scorching, which will progressively lose max health
  • Has a custom screen overlay 
  • By default it applies on mesa biomes
  • Can be counteracted with Vanilla's water bottle as well, by increasing the cooldown
  • Advanced explanation

    Sweltering is an effect that acts like a timer, warning, and barrier to scorching which causes detrimental effects. In other words, while under the specified conditions, the player will always be either affected by sweltering, scorching, or gale barrier.
    Specific biomes and coordinates in which sweltering and scorching will be permanently applied can be configured.
    If the player moves from a biome or coordinate that causes sweltering/scorching these effects to another biome or coordinate that also causes effects, their timer will remain. The timer will reset and disappear when entering a biome or coordinate that doesn't cause effects: If moving from the nether with 57 seconds left of sweltering to a biome that causes sweltering II, the timer will remain and continue at 57 seconds.
    The sweltering effects can be "filled up” or recharged while in the biome by external means: drinking a potion that gives sweltering for 3 minutes while having 10 seconds left will set the timer to 3 minutes. As long as the player is sweltering, nothing will happen. When sweltering reaches 0, they will be affected by the corresponding level of Scorching.
    Gale Barrier: For each level of this effect, it stops the timer for the corresponding level of Sweltering (it doesn’t help with Scorching unless the player recharges the timer above 0).
    Sweltering I: When the potion timer reaches 0, the effect will be replaced by Scorching I, and the player will lose one max health down to a minimum of 10 health (5 hearts) each second. Two maximum health points can be regained by drinking the specified items (default: water bottle). All max health can be regained quickly and scorching removed by exiting the specified biome/coordinates or by increasing the sweltering effect again.
    Sweltering II: When the potion timer reaches 0, the effect will be replaced by Scorching II, and the player will lose two max health down to a minimum of 10 health (5 hearts) each second. If at 10 max health (after reaching the minimum), the player will continue to receive fire damage for 1 health each second until they die, get rid of the effect by recharging sweltering II, or exit the biome/coordinates.
    Sweltering III: is the same as above, except it requires the corresponding effect of Gale Barrier/Sweltering to prevent Scorching III.

• Gale Barrier: For each level of this effect, it stops the timer for the corresponding level of Sweltering
• Freezing/Cooling: Freezing damages the player each X ticks and slows them down. Similarly to Sweltering, it only becomes dangerous after a configurable amount of time is spent in a biome or standing on a block (runs on an invisible timer). Cooling is an instant effect that can force freezing outside of the configured conditions for a certain amount of time per level (more details later on mod description page)
  • Has a custom screen overlay
  • By default it applies on cold taiga biomes
  • Advanced explanation

    Potion effect. There are two ways to get the Freezing effect, via TicksFrozen or via cooling. While freezing the player’s hearts get a cyan overlay, and take 1hp of damage each 40 ticks. Additionally, while freezing or TicksFrozen <50% (I.e. while there’s a visible cyan overlay) the player moves 10% slower
    TicksFrozen is a counter that runs backwards for a configurable amount of time (for example 400 ticks) while inside specified biomes or while on top of specified blocks. when the counter passes <50% of the defined amount, a frozen vignette will fade in on the player’s screen. Once it reaches 0, the player will suffer freezing permanently until the counter gets over >50% again. 
    cooling is an instant potion effect; when affected by it, it will forcefully trigger TicksFrozen at double the default speed until it reaches 0, and inflict freezing for a configurable amount of time for each level of potency.
    For example, configured for each level of cooling to give 2 seconds/80 ticks with TicksFrozen at 400 ticks, cooling III would take 200 ticks to give the player freezing for 6 seconds/240 ticks
    Warming is an instant potion effect; when affected by it, it will forcefully increase TicksFrozen at three times the default speed and give immunity to freezing for a configurable amount of time for each level of potency.

• Warming: Instant effect that quickly removes freezing and gives immunity to it
• Cardiac Arrest: Player max health is reduced to 1, locked with a chain to prevent regeneration; and is blinded. On effect end, healthbar goes back to normal (For those that have unimaginable eldritch horrors in their modpacks! or realistic cholesterol)
  • Has a custom GUI overlay
• Strong Heart: Entirely prevents Cardiac Arrest while active

New items

• Smelting Vessel: A throwable item that can store custom item NBT. When thrown, it will break on impact and drop the defined items
  • Can be used as a way to give players mistery loot, or for immersive smelting of items (custom recipe with raw ore, cook vessel to output a vessel containing the refined ingot), or anything you can think of
  • Example /give @p rotntweaker:smelting_vessel 1 0 {storedItems:[{id:"minecraft:diamond",Count:1},{id:"minecraft:iron_ingot",Count:3}]}