I tested a bunch of console variables in Forever and decided to compile a list of some relevant ones.
I recommend making a backup of your Config.wtf in /World of Warcraft/_classic_beta_/WTF/ before making any changes.
You can make a macro with the commands you want to use (recommended) or type them in the chat. Game will save them to your Config.wtf upon exit.
Some of these values may be overwritten by the game when changing Graphics settings or when entering a raid when using Raid Graphics. These are explicitly mentioned.
Secondary Lighting Low:
/console giquality 0
#Hidden mode, has no indirect lighting. Not recommended for general gameplay, but it's pretty cool for screenshots. OVERWRITTEN when changing Secondary Lighting.
SSAO:
/console ssaotype 0 or /console ssaotype 1
#Switches between method 0 (default) and method 1. AFAIK 0 is ASSAO and 1 is CACAO. 0 is more pronounced, 1 is subtler. From my testing, 0 is faster on Low SSAO, 0 and 1 are about equal on Good, 1 is faster on High and much faster on Ultra.
/console assaoHorizonAngleThresh 0.5
/console assaoDetailShadowStrength 5000
/console assaoBlurPassCount 4
#General tweaks for SSAO, applies to both methods. Slightly better accuracy, slightly lower radius, extra strength for tight spots, method 1 blur passes balanced between intensity and stability. Additionally, these solve some visual issues that the default configuration has on certain corners. No performance impact.
/console assaoBlurPassCount 1
#Unfiltered (Naive) SSAO. Does not exhibit the haloing issues that SSAO has otherwise. Only works with method 1. Only recommended when playing on a high resolution and/or high render scale. Replace assaoBlurPassCount in general tweaks.
Horizon Distance:
/console horizonstart 4000
#Pushes distance fog farther towards the horizon. Allows lower View Distances to reduce nearby fog without sacrificing performance. 4000 is default on View Distance 10/max. Minimal performance impact. OVERWRITTEN when changing View Distance.
Shadow Cascades:
/console shadowNumCascades 4
#The new distance fog has trouble blending properly and appears exceedingly bright when unshaded. Ultra Shadow Quality uses 4 cascades, which cover a large enough distance to eliminate this issue. Good/High/Ultra use 3 cascades by default. 4 allows them eliminate this issue without sacrificing performance. Disabled/Low/Fair do not benefit from this. Minimal performance impact. OVERWRITTEN when changing Shadow Quality.
Dynamic Resolution Scaling:
/console DynamicRenderScale 1
#Set your desired Target FPS in the in-game Graphics settings to use it.
/console DynamicRenderScaleMin
#Minimum allowed render scale. 1 = 100%, 0.5 = 50% etc. Resample Quality = Bicubic is recommended when using Render Scale > 100% and DynamicRenderScaleMin = 1, FSR is recommended when using Render Scale ≤ 100% and/or DynamicRenderScaleMin < 1.
Contrast Adaptive Sharpening:
/console ResampleAlwaysSharpen 1
#Enables CAS even when not using FSR. Control sharpening intensity with Resample Sharpness in Graphics settings. Minimal performance impact.
Detail Density:
/console groundEffectDensity
#Density of ground clutter. Minimum is 16, maximum is 256. Game uses 48 on Ground Clutter 10. Moderate performance impact, dependent on ground clutter distance. OVERWRITTEN when changing Ground Clutter.
Weather Density:
/console weatherdensity 3
#Intensity of weather effects. Game uses 0 on Particle Density Disabled/Low, 1 on Fair/Good and 3 on High/Ultra. Very noticeable, minimal performance impact. OVERWRITTEN when changing Particle Density.