Teleport to Nether:
/execute in minecraft:the_nether run teleport ~ ~ ~

Teleport to The End:
/execute in minecraft:the_end run teleport ~ ~ ~

Teleport to Overworld:
/execute in minecraft:overworld run teleport ~ ~ ~

Stop time:
/gamerule doDaylightCycle false

Blindness:
/effect give @p blindness 99999

Remove effects:
/effect clear @p

Lightning bolt:
/summon lightning_bolt [pos]

Moon phase:
/time set 18000 - Full Moon
/time set 44000 - Waning Gibbous
/time set 68000 - Last Quarter
/time set 92000 - Waning Crescent
/time set 116000 - New Moon
/time set 140000 - Waxing Crescent
/time set 164000 - First Quarter
/time set 188000 - Waxing Gibbous