Quick Spell Side FX

0-2nd lv spells > 3-5 lv spells > 6+
Not really sure what to do with this just seemed like an idea
Modern players do this lots anyway but maybe this suggests a range of spectacularness

All fx temporary maybe a d4 rounds or the level lof spell

Players should make their own or choose one for their signature style

d12 Divine Spell Side Effects
1 Eyes change colour > eyes glow > eyes smoke and crackle

2 Booming voice > eldritch chanting > air vibrating and unearthly cacophony

3 Halo or aurora as lamplight > body glows > area bathed in an unearthly light

4 Holy Symbol glows like a candle > hums and lights as torch > chants and lights as lamp  

5 Sparkling particles > globes of light fly around caster > small fluttering planar beings swarm around like cherubim or imps or daimon spirits depending on alignment

6 Vapour comes from caster > fog cloud grows 3m per round > swirling vapours grows 

7 Boom sound > gust of air radiates from caster in a 6m circle > screeching klaxon grates teeth in hearing range

8 Musical note > eerie music of the spheres > single booming drone shakes earth and air

9 Face features change > mask appears over face > appears like a holy supernatural being

10 Holy words form around caster > glowing symbol over caster > glowing phrases fly around the area from the caster

11 Become slightly blurry > buzzing sound and indistinct blurry form > leave a bizarre visual echo trailing behind them of ghost images

12 Skin and hair change colour > clothing changes > body crackles with power 

d12 Arcane Spell Side Effects
1 Eyes change colour > eyes glow > eyes smoke and crackle

2 Sneeze > face swells, nose and mouth running phlegm and foaming > vomits spectacular stream or weird coloured slime

3 Skin sags > appear old and wizened > horrifically skeletal living corpse appearance

4 Hair grows > hair grows a foot/30cm > hair grows yard/metre and is animated

5 Gain temporary minor mutation > temporary major mutation > temporary minor and major mutation

6 Nubbly horns of energy appear > glowing horns grow to 30cm> horns over a metre

7 Become slightly blurry > buzzing sound and more indistinct blurry film > leave a bizarre echo trailing behind them of ghost images

8 Flash of light from mouth > fire blazing from mouth > fiery words fly around

9 Light frost appears on caster > ice and icicles form on caster > area filled with snowflakes

10 Hair alight > body alight > swirling firey sparks swirl around caster igniting flammables

11 Vapour comes from caster > fog cloud grows 3m per round > swirling vapours grows 

12 Shrouded in shadow > jet black shroud > area shrouded in dim light or shadow

d12 Mentalism Spell Side Effects
1 Eyes change colour > eyes glow > eyes smoke and crackle

2 Blood nose > blood from eyes > soaked in blood and dripping

3 Halo or aurora as lamplight > body glows > area bathed in an unearthly light

4 Become slightly blurry > buzzing sound and more indistinct blurry film > leave a bizarre echo trailing behind them of ghost images

5 Shrouded in shadow > jet black shroud > area shrouded in dim light or shadow

6 Strane voice barks strange words in alien voice > air pressure increases > everyone in area save or get a blood nose and headache

7 Vapour comes from caster > fog cloud grows 3m per round > swirling vapours grows 

8 Skin sags > appears withered > horrifically skeletal living corpse appearance

9 Muscles bulge and ripple > muscles swell uncannily and spasm > body swells with a scream and gains 30cm/foot height 

10 Small objects rattle > objects shake and rattle around caster > psychokinetic storm of garbage and ectoplasm

11 Extoplasmic dew forms on surfaces > caster dripping with ectoplasmic slime > area showered in slime

12 Seems to move uncannily > seem to move in stuttering motion > everyone in area  feels like moving in slow motion

d12 Nature Spell Side Effects
1 Eyes change colour > eyes glow > eyes smoke and crackle

2 Bestial eyes > bestial face > humanoid beast creature form

3 Sprout leaves or flowers > hybrid plant humanoid > shambling plant or tree figure

4 Fungus sprouts on body > hybrid fungus humanoid > shambling mushroom or fungus figure

5 Crack thunder-like sound > cold winds around caster > storm-like conditions in the area

6 Ground Shakes > walls shake and some property damage > quake over area

7 Caster wet > buckets of water leaks from them > area raining even indoors might rise tide speed at sea

8 FIre brightens in area > fire sources blaze and grow > objects in area spontaneously combust and caster on fire but unharmed

9 Insects and worms appear around caster > swarming bugs fly around caster  > area swarming with flying and crawling bugs 

10 Tiny faces appear on clothes > wee faeries fly and crawl around caster > area full of tiny squealing faeries

11 Tiny light motes form around caster > tiny spirits swarm around caster > swarm around the whole area

12 Draconic eyes > scaly skin > spectral wings and tail and draconic face

I am still thinking about spell components also 
gesture material vocal elements
(i add visual fx like these tables above also you can minimise including these for more stealthy magic)
I think they are kind of fluff but also to limit what spell casters can do
I think making them part of spellcasting is ok 
There were abilities in some games to not require a specific component
But now in the principle of making things rewarding instead of punishment maybe some benefit or reward for doing more

Like
gesture with a hand might require a dance instead of using the whole body
material using extra fancy or expensive ingredients is a bonus
verbal is more shouty or musical maybe use a musical instrument

ill keep thinking

also made a solid way to fix a big mythical problem I was having with my universe