Euler's game, grasshopper arena and courier chess are all underrated
Underrated variants

I'd say Tinyhouse and Cross Derby. Tinyhouse is one of the very rare ones with only an 4*4 board and 5 pieces for each player, but is rather tactical and complex; Cross Derby is unique because the only pieces are in practice pawns and knights (not even kings) and it produces attacking play. Mini Forest is pretty fun as well imo

Every variant is underrated because only 1% of chess.com plays it.
On a more real note, all custom variants receive very little love after a month they've been released

thermopylae
Thermopylae is one of the more popular variants. See how long it takes to fill a seek for Chaturdrez.

2b, are you mad at me? do you just monitor chess.com for me to make a comment so you can contradict it. With all due respect--
Bruh

2b, are you mad at me? do you just monitor chess.com for me to make a comment so you can contradict it.
wdym
Oh did I sound rude? Sorry if I sounded rude, I was trying to use an objective tone there.

nah not here so so much but when I made that "spam" forum you were like , "yeah, kiddo". Using like a superior attitude

nah not here so so much but when I made that "spam" forum you were like , "yeah, kiddo". Using like a superior attitude
I apologise sincerely if I came across that way. I often use slang from my dialect, and in that "kiddo" means "dude." I apologize, once again, if my tone sounded egotistical.

For me, the most underrated by myself is No Castling. To me it’s basically regular chess with one rule removed, so it doesn’t feel as exciting or as fresh as many other variants.
What do u think are underrated variants tell me in the comments